Abstract: OBJECTIVE To evaluate the risk of cognitive impairment caused by proprotein convertase subtilisin/kexin type 9 inhibitors(alirocumab, evolocumab), and to provide reference for clinical safe use. METHODS According to MedDRA standard dictionary, cognitive impairment was divided into two parts: broad cognitive impairment and narrow cognitive impairment, and corresponding search terms were obtained. Using the openFDA database, the search period was from the date of FDA approval for these two drugs to September 18, 2021. Simultaneous signal detection using proportional reporting ratio(PRR) method and bayesian confidence propagation neural network method. RESULTS A total of 1 144 adverse events of cognitive impairment caused by alirocumab were retrieved, the 95%CI(PRR) lower limit of the overall risk was 0.81, and the IC-2SD value was -0.43. Three weak positive signals of amnesia, memory impairment and feeling abnormal were detected in the adverse events related to broad cognitive impairment by the two methods, and no signal was detected for adverse events related to narrow cognitive impairment; There were 3 632 adverse events of cognitive impairment caused by evolocumab, the 95%CI(PRR) lower limit of the overall risk was 0.58, and IC-2SD value was -0.86. Two weak positive signals of memory impairment and feeling abnormal were detected in the adverse events related to broad cognitive impairment by the two methods, and no signal was detected in the adverse events related to narrow cognitive impairment. CONCLUSION Although positive signals were detected for both PCSK9 inhibitors in the adverse events related to broad cognitive impairment, the signal intensity is weak, the specific correlation with drugs is small, and the risk of cognitive impairment is low. This conclusion needs to be further verified.