Objective: To observe the intraoperative influences on pharmacodynamics of rocuronium in children inhaling sevoflurane and desflurane for 40 min balance. Methods: Ninety children (ASAⅠ-Ⅱ) undergoing elective surgery with general anesthesia in Second Affiliated Hospital & Yuying Children's Hospital, Wenzhou Medical University from July 2015 to May 2016 were randomly assigned into six groups (n=15): Sevoflurane group (group S1 and S2), Desflurane group (group D1 and D2) and Propofol group (group P1 and P2). Children in group D1, S1 and P1 were allocated to research the dose-effect relationship of rocuronium, children in group D2, S2 and P2 were allocated to research the time-effect relationship of rocuronium. TOF-Watch SX monitor was used to exert a train-of-four stimulation (TOF) at ulnar nerve in wrist, then the adductor pollicis muscle appeared muscle twitch 4 times in turn which was recorded T(1, )T(2, )T(3) and T(4) respectively. After the success of the muscle relaxant calibration, 1.3 MAC sevoflurane and desflurane were inhaled and maintained for 40 min respectively in children in Sevoflurane group (group S1 and S2) and Desflurane group (group D1 and D2), Plasma target controlled infusion of 3.5-4.0 μg/ml propofol was always administered in Propofol group (group P1 and P2). 75 μg/kg rocuronium was injected each time in group S1, D1 and P1 respectively. Maximum inhibited effect of T(1) was recorded after every injection until inhibition of T(1) more than 95% eventually. The method of cumulative dose four times was used to calculate the efficiency curve of rocuronium[median effective dose (ED(50)), 90% effective dose (ED(90)) and 95% effective dose (ED(95))]. 0.6 mg/kg rocuronium was injected respectively through vein in group S2, D2 and P2. The recovery times of muscle relaxant were recorded which including time of T(1) disappeared (onset time), T(1) from 0% to 5% (peak effect time), T(1) from 0% to 25% (clinical effect time), T(1) from 25% to 75% (recovery index), T(1) from 0% to 70% (internal effect time), T(4)/T(1) (TOFr) from 0% to 70% and 90%. Results: ED(50, )ED(90) and ED(95) in group D1 were 128.73, 212.45 and 245.78 μg/kg respectively. ED(50, )ED(90) and ED(95) in group S1 were 132.46, 218.94 and 252.30 μg/kg respectively. ED(50, )ED(90) and ED(95) in group P1 were 230.56, 381.02 and 439.55 μg/kg respectively. ED(50, )ED(90) and ED(95) in group D1 and S1 were significantly lower than those in group P1 (all P<0.05), but there was no significant difference between D1 and S1 group (P>0.05). Compared with group P2, the shorter onset time, the longer peak effect time and clinical effect time was observed in group D2 and S2, the longer recovery index, internal effect time and TOFr from 0% to 70% and 90% was observed in group S2 (all P<0.01). Conclusions: 1.3 MAC sevoflurane and desflurane inhaling for 40 min significantly reduces ED(50) and ED(95) of rocuronium, prolongs the onset time and action time of rocuronium in children. Sevoflurane can significantly prolong the recovery characteristics of rocuronium.