Objective To discuss the influence of pudendal nerve block anesthesia on pain degree and labor course when presentation at different positions during the second stage of labor,in order to find the better anesthesia timing and method to reduce pain,shorten labor,increase maternal comfort to a maximum extent and provide the best service for the maternal.Methods 200 cases of primiparas with fullterm and single-birth were selected and numbered randomly,patients with odd numbers were set to the observation group,patients with even numbers were set to the control group,100 cases in each group.In the observation group,when the presentation reached S+1,1％ lidocaine was used to perform pudendal nerve block anesthesia.In the control group,the pudendal nerve block anesthesia was performed before perineal incision.Results The pain intensity,time of the second labor stage,perineum damage degree between the two groups were statistically different.The observation group with Ⅱ-grade level,Ⅲ-grade level pain were 32 cases less than that of the control group.The perineum incision later crack number in the observation group was 24 cases less than that of the control group.The number of delivery within 1 hour in the second labor process in the observation group was 21 cases more than that in the control group.Conclusions Implementation of bilateral pudendal nerve block anesthesia in the second stage of labor when the presentation reaches S+1 can alleviate childbirth pain,shorten the second stage of labor,reduce the degree of perineal trauma.