Objective To systematically retrieve and analyze case-control studies in traditional Chinese medicine（TCM） to understand possible problems in methodology quality and reporting quality. Methods PubMed

Embase

CBM

CNKI

VIP and Wanfang were systematically searched from database establishment to December 31

2018 for literatures on case-control study in TCM. The included literatures were evaluated by an assessment tool of methodology quality recommended by The Cochrane Collaboration

Newcastle Ottawa Scale（NOS）

and Strengthening the Reporting of Observational Studies in Epidemiology（STROBE statement） checklist（introduction and methods sections）

respectively. The literatures were summarized and analyzed by applying the method of qualitative description. Linear trend test and Spearman rank correlation analysis were used to analyze the correlation between NOS quality grades and reporting percentages of STROBE checklist items. Results A total of 289 literatures were finally included. TCM syndromes

symptoms and constitutions are core topics of case-control studies in TCM. Methodological evaluation on the literatures showed that low-quality literatures（3-4 points） accounted for 17. 0%（49 literatures）

medium-quality literatures（5-6 points） accounted for 59. 8%（173 literatures）

and high-quality literatures（7-8 points） accounted for 23. 2%（67 literatures）. The results of reporting quality evaluation found that most of the literatures did not report complete information. Application of matching

bias control and quality control were short of necessary details

but the reporting on the purpose and statistical analysis of the study were explicit. The correlation analysis found that the methodology quality of the literatures was weakly correlated with the reporting quality（r = 0. 246

P < 0. 001）. Conclusion The overall quality of the case-control studies in TCM was acceptable

but there were few high-quality literatures. There were problems of inadequate reporting of matching

quality control and other aspects.