Abstract: In order to ensure the safety and efficacy of generic drugs for the substitution of narrow therapeutic index (NTI) drugs, and to improve and optimize China's generic drug substitution policy, we searched foreign literature databases and government websites to collect and sort out the typical measures taken by some foreign countries to ensure the safety and efficacy of generic drugs for the substitution of NTI drugs, including R&D registration, generic drug substitution and post-market surveillance. On the basis of comparative analysis, this paper summarizes the practices China can learn from. It can be seen that there are problems and challenges in China's generic drug substitution for NTI drugs, such as unclear targets for bioequivalence studies of NTI drugs, insufficient rational decision-making basis for generic substitution of NTI drugs, and imperfect post-market surveillance system, etc. It is recommended that we should formulate a list of NTI drugs, play the roles of physicians and pharmacists in generic drug substitution, adjust the generic drug substitution for NTI drugs according to the level of risk of drug use, and improve the reporting system for adverse reactions due to generic drug substitution.