Objective: To explore the effect of standardized diagnosis on hospital cost control under the CHS-DRG payment. Methods: Formulating the workflow of hospital standardized diagnosis, embedding in electronic medical records, and combining with the CHS-DRG management system, so that the clinic can clearly understand the profit and loss situation before the upload of medical insurance cases, so as to achieve the purpose of affecting medical expenses and evaluate the effect before and after the process. Results: The accuracy of clinically written diagnostic information was greatly improved after the standardization of diagnosis; the cost of most sample departments decreased after the standardization, which was mainly reflected in the proportion of drugs and consumption. The cost continues to decrease month by month in Endocrinology, which is not the case in other departments. Conclusion: Under the CHS-DRG payment system, the standardization of diagnosis based on clinical participation in matching ICD codes, with the help of DRG management system, can help internal medicine department to reduce medical expenses and control medical costs. In order to further reduce medical costs, it is recommended to standardize operations by focusing on operating departments.