OBJECTIVE To exc avate and evaluate the adverse reaction signals of 4 kinds of imported programmed cell death 1 （PD-1）and its ligand （PD-L1）inhibitors，and to guide rational drug use in clinic. METHODS OpenVigil 2.1 software was used to obtain the adverse event reports of four drugs as nivolumab ，pembrolizumab，atezolizumab and durvalumab from the first quarter of 2013 to the fourth quarter of 2020 in the US FDA adverse event reporting system. The reporting odds ratio and proportional reporting ratio were used for signal mining to evaluate new or potential adverse reaction signals. RESULTS A total of 46 840 reports of adverse events with PD- 1/PD-L1 inhibitors as the primary suspected drug were collected ，including 28 896 reports of nivolumab，13 298 reports of pembrolizumab ，3 398 reports of atezolizumab ，and 1 248 reports of durvalumab. From the general characteristics of these reports ，the gender distribution was more men than women ，and the age distribution was mainly in the range of 51-85 years old. The reporting year was mainly in the nearly 4-5 years，and the main reporting countries were the US and Japan，with“death”and“hospitalization or prolonged hospitalization ”as the main serious adverse events which were over 50％ of the whole of 4 kinds of adverse events. A total of 1 597 adverse reaction signals were obtained ，involving 26 systems，focusing on “benign，malignant and unspecified neoplasms （cystic and polypoid tumor ）”，“infections and infestations ”and“investigations”， etc. The analysis of the top 50 adverse reaction signals showed that the largest number of report was endocrine system disease ，the most frequency signal was “malignant neoplasm progression ”and the strongest adverse reaction signal was “radiation pneumonitis ”. And it was also found that 13 adverse reaction signals ，such as “radiation pneumonitis ”“cholangitis”“fulminant type 1 diabetes mellitus” “blood creatine phosphokinase increased ” “disseminated intravascular coagulation ”“cardiac failure ”and “cerebral infarction ”，etc.，were not reported in the drug instructions. CONCLUSIONS PD-1/PD-L1 inhibitors mediate a large number of adverse reaction signals，resulting in high safety risks in “benign，malignant and unspecified neoplasms （cystic and polypoid tumor ）”，“infections and infestations ”and “investigations”，etc. The newly discovered 13 adverse reaction signals ，such as “radiation pneumonitis ”“cholangitis”“blood creatine phosphokinase increased ”“cardiac failure ”and“cerebral infarction ”are of great significance for guiding rational drug use in clinic.