Background Phlegm and blood stasis syndrome (PBSS) is one of the main syndromes in coronary heart disease (CHD).Syndromes of Chinese medicine (CM) are lack of quantitative and easyimplementation diagnosis standards.To quantify and standardize the diagnosis of PBSS,scales are usually applied.Objective:To evaluate the diagnostic accuracy of CM diagnosis scale of PBSS in CHD.Methods:Six hundred patients with stable angina pectoris of CHD,300 in case group and 300 in control group,will be recruited from 5 hospitals across China.Diagnosis from 2 experts will be considered as the “gold standard”.The study design consists of 2 phases:pilot test is used to evaluate the reliability and validity,and diagnostic test is used to assess the diagnostic accuracy of the scale,including sensitivity,specificity,likelihood ratio and area under the receiver operator characteristic (ROC) curve.Discussion:This study will evaluate the diagnostic accuracy of CM diagnosis scale of PBSS in CHD.The consensus of 2 experts may not be ideal as a “gold standard”,and itself still requires further study.(No.ChiCTR-OOC-15006599).