Objective To observe the pharmacodynamic characteristics of different doses of cis-atracurium used in laparoscopic surgery on children.Methods 80 cases of selective laparoscopic surgery on children were randomly divided into 2 groups, 2 ED95 (Ⅰ group) or 3 ED95 (Ⅱ group) of cis-atracurium were intravenously given respectively.Record two group's muscle block time-effect and intubation conditions to observe the onset time of block, TOF-free response period, duration of anesthesia, muscle relaxation index and time in vivo recovery.Results Tracheal intubation in group Ⅱ with muscle relaxant block and intubation conditions better than groupⅠ;onset time of muscle relaxation in group Ⅱshorter than that in groupⅠ;TOF non-response period, maintain time of block and the time of function in vivo of two groups were different significantly;muscle recovery index were not significantly different Conclusion 3ED95 inducing dose of cis-atracurium effect on children with fast and excellent intubation conditions, and no response to TOF period and maintain time of block and the time of function in vivo longer than 2ED95 dose cis-atracurium;two groups had no significant difference in recovery index.