Objective Observed and compared vecuronium in young and middle-aged female patient neuromuscular blocking effect. Methods Forty breast mass excision female patients with ASA I-II were divided into young (18-44 years old) and middle-age group (45-59 years old),with 20 patients each . Vecuronium of 2ED95(0.1mg/kg) was injected during anesthesia induction, using TOF-Watch acceleration monitoring instrument for muscle relaxation, Thumb adductorius contractile response was monitored with train of four(TOF) stimulation. The time of neuromuscular block onset, duration of blockade maintenance, duration of in vivo action, recovery index and the time of TOF ration of recovery to 25% were recorded. Results Youth group muscle relaxant onset time, duration of action in vivo and TOF recovery to 25% of the time were significantly shorter than the middle-aged group (156±33s、186±44s；66.6±29.3min、76.9±19.6min; 47.5±13.6min、60.5±15.9min,P<0.05）. There were on significant difference in duration of blockade maintenance（36.9±10.5min、42.9±11.4min,P>0.05） and neuromuscular block recover index（20.7±17.1min、22.3±12.6min,P>0.05） among two groups . Conclusion Compared to patients with middle-aged women, young female patient more sensitive,, with faster neuromuscular block onset, shorter duration of clinical action , but had no effect on the recovery process of muscle relaxants.