To analyze the clinical characteristics of 216 patients with non-ST segment elevation myocardial infarction (NSTEMI). Methods A retrospective analysis was used. Two hundred and sixteen NSTEMI patients were divided into two groups: ① according to the age: age <65 years group and age ≥65 years group; ② according to thrombolysis in myocardial ischemia trial (TIMI) IIB risk stratification scoring system: score <4 group and ≥4 group; ③ according to serum creatinine (sCr) level: sCr level ≤178 μmol·L-1 group and >178 μmol·L-1 group. Seven hundred and eighty six acute myocardial infarction (AMI) patients during the same period were divided into ST segment elevation myocardial infarction (STEMI) group and NSTEMI group. Clinical characteristics of the patients in the two groups were compared. Results ① The number of NSTEMI patients in age ≥65 years group is significantly greater than that in age<65 years group. Study revealed that the patients in age ≥65 years group were without chest pain, had hypertension, dyslipidemia, atrial fibrillation, cardiac and renal dysfunction (sCr>178 μmol·L-1)and triple vessel disease. Fewer patients in this group received coronary artery angiography (CAG), percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG). More number of deaths in this group compared with the age <65 years group. ② The number of NSTEMI patients in TIMI score >4 group is significantly greater than that in TIMI score<4 group. Four major complications such as acute left ventricular failure, cardiogenic shock, serious arrhythmia and deaths, increased significantly in TIMI score >4 group comparing with TIMI score ≤4 group. ③ Obviously, more number of elderly patients, non-insulin dependant diabetes mellitus (NIDDM), patients with cardiac troponin T(CTnT) >3.0 ng·L-1 and deaths occurred in sCr >178 μmol·L-1 group. ④ STEMI and NSTEMI patients were compared in same time frame as follows: fewer NSTEMI patients and more elderly patients had no chest pain, NIDDM, hypertension, dyslipidemia, left main coronary artery (LMCA) disease while CTnT ≥3.0 ng·ml-1; fewer patients with aneurysm (30 days) underwent CAG, PCI and CABG treatment. However, there were no significant differences in smokers, patients with less than 50% stenosis in any vessel, 1-3 vessel disease, acute left ventricle heart failure, cardiogenic shock, serious arrhythmia and deaths. ⑤ The multivariate logistic regression analysis showed that death in NSTEMI was directly influenced by malignant arrhythmias with age≥70 years. Conclusions Patients with NSTEMI were older, had more risk factors and presented more serious vessel disease, therefore, less of them could receive standard treatment. Complications and mortality of patients with NSTEMI were similar to that of patients with STEMI. Thus, NSTEMI is a serious disease with poor prognosis. NSTEMI patients may present with atypical chest pain and electrocardiogram changes, so are easily missed or loss diagnosed. To analyze the clinical characteristics of 216 patients with non-ST segment elevation myocardial infarction (NSTEMI). Methods A retrospective analysis was used. Two hundred and sixteen NSTEMI patients were divided into two groups: ① according to the age: age <65 years group and age ≥65 years group; ② according to thrombolysis in myocardial ischemia trial (TIMI) IIB risk stratification scoring system: score <4 group and ≥4 group; ③ according to serum creatinine (sCr) level: sCr level ≤178 μmol·L Seven group and> 178 μmol·L-1 group. Seven hundred and eighty six acute myocardial infarction (AMI) patients during the same period were divided into ST segment elevation myocardial infarction (STEMI) group and NSTEMI group. Clinical characteristics of the patients in the two groups were compared. Results ① The number of NSTEMI patients in age ≥65 years group is significantly greater than that in age <65 years group. Study revealed that the patients in age ≥65 years group were w Fewer patients in this group received coronary artery angiography (CAG), percutaneous coronary intervention (PCI), thrombocytopenic purpura, and coronary artery bypass graft (CABG). More number of deaths in this group compared with the age <65 years group. ② The number of NSTEMI patients in TIMI score> 4 group is significantly greater than that in TIMI score <4 group. Four major complications such as acute left ventricular failure, cardiogenic shock, serious arrhythmia and deaths, increased significantly in TIMI score> 4 group comparing with TIMI score ≦ 4 group. ③ Obviously, more number of elderly patients, non-insulin dependent diabetes mellitus (NIDDM ), patients with cardiac troponin T (CTnT)> 3.0 ng · L-1 and deaths occurred in sCr> 178 μmol·L-1 group. ④ STEMI and NSTEMI patients were compared in the same time frame as follows: fewer NSTEMI patients and more e lderly patients had no chest pain,NIDDM, hypertension, dyslipidemia, left main coronary artery (LMCA) disease while CTnT ≥ 3.0 ng · ml-1; fewer patients with aneurysm (30 days) underwent CAG, PCI and CABG treatment. However, there were no significant differences in smokers, patients with less than 50% stenosis in any vessel, 1-3 vessel disease, acute left ventricle heart failure, cardiogenic shock, serious arrhythmia and deaths. ⑤ The multivariate logistic regression analysis showed that death in NSTEMI was directly influenced by malignant arrhythmias with age More than 70 years. Conclusions Patients with NSTEMI were older, had more risk factors and presented more serious vessel disease, therefore, less of them could receive standard treatment. Complications and mortality of patients with NSTEMI were similar to that of patients with STEMI. Thus, NSTEMI patients may present with atypical chest pain and electrocardiogram changes, so are easily missed or loss diagnosed.