Objective To identify the independent risk factors for the patients with surgical site infections (SSI) after spinal surgery based on available evidence in the literature.Background.Surgical site infections (SSI) lead to higher morbidity, mortality and increased healthcare costs.Various risk factors influence the postoperative infections.Disclosure which factors lead to an increased risk of SSI is of importance for the development of prophylactic protocols to counter this risk.However, these factors have neither been well synthesized or summarised according to methodological quality of studies evaluating risk factors for SSI.Methods Non-interventional studies evaluating the independent risk factors for the patients with SSI following spinal surgery were searched in Medline, Embase, Sciencedirect and OVID.Quality of included studies were assessed by a modified quality assessment tool, which was previously designed for observational study.The effects of studies were combined with the study quality score using a model of best-evidence synthesis.Results 35 observational studies involving 24, 774 subjects were identified.Included studies covered a wide range of indications and surgical procedures.These articles published between 1998 to 2012.According to the quality assessment criteria for included studies, 14 studies were deemed as high quality studies, 5 as moderate quality studies, and 16 as low quality studies.A total of 46 different type of independent factors were evaluated for the risk of SSI.There were strong evidence for 6 factors, including obesity/BMI, longer operation time, diabetes, smoking, history of previous SSI and type of surgery procedure.We also identified 8 moderate evidence, 31 limited evidence and one conflicting evidence factors.Conclusion Whilst there is no conclusive evidence for the postoperative SSI, these data provide evidence to guide the clinician to admit patients who will have spinal operation and to choice a optimal prophylactic strategy.Further researches were still required to evaluate the effects of these above factors.