Objective To investigate the neuromuscular block effect of intravenous injection of two times of 95% effective dose (ED95) of cisatracurium in patients with different ages. Methods Sixty patients with ASA Ⅰ-Ⅱ were divided into children group (3 to 7 years old), youth group (18 to 65 years old) and elder group (≥ 65 years old), with 20 patients in each group. Cisatracurium of two times of ED95 was injected during anesthesia induction, neuromuscular block was monitored with TOF Watch acceleration instrument, and the time of neuromuscular block onset, duration of blockade maintenance, duration of clinical action, duration of in vivo action and neuromuscular block recovery index were obtained. Results There was no significant difference in trachea intubation grading among three groups （P＞0.05）. The time of neuromuscular block onset, duration of blockade maintenance, duration of clinical action and duration of in vivo action in children group were significantly shorter than those in youth group and elder group (P<0.05). There was no significant difference in neuromuscular block recovery index among three groups （P＞0.05）. Conclusion Children are more sensitive than adults to cisatracurium, with faster neuromuscular block onset, shorter duration of blockade maintenance and shorter duration of clinical action. The neuromuscular block recovery time is not related to age, and two times of ED95 of cisatracurium is safe and effective for patients with different ages.