Purpose/Significance To analyze the main problems and preprocessing technical methods of clinical structured data in clinical retrospective studies,so as to provide new perspectives for clinical data preprocessing research.Method/Process On the basis of more than 10 years historical data governance in several medical centers of the PLA General Hospital,a set of preprocessing methods focusing on data fusion,simplification and cleaning are sorted out,and the effects are summarized.Result/Conclusion Data preprocessing solves the common problems of historical data in clinical research and reduces the workload of data secondary processing.The clinical research retrieval system is established on this basis to effectively improve the availability and value of data.