Abstract: Objective:To investigate the effect of atropine combined with penehyclidine on patients with severe acute organophosphorus pesticide poisoning (AOPP).Method:Acute AOPP patients,who was admitted to ICU from July 2013 to July 2017 in our hospital,were divided into group A (atropine treatment group,n=36),group B (penehyclidine treatment group,n=36) and group C (combined treatment group,n=36).CHE activity was examined dynamically.The length of hospital stay,intermediate syndrome and adverse reactions were recorded.The cure rate was counted.Result:①The time of recovery of CHE activity to 70% in group A,group B and group C were (101.86±9.2) h、(80.38±9.37) h、(74.66±7.25) h respectively,and the length of hospital stay were (13.11±2.48) d、(12.07±1.63) d、(9.76±1.80) d respectively.The time of recovery of CHE activity to 70% and the length of hospital stay in group C decreased than those in group A and B,and those of group B reduced than the group A.the differences were statistically significant (all P<0.05).②Compared with group A,the incidence of intermediate syndrome and adverse reactions in the group C were decreased obviously,and the cure rate was increased.Adverse reactions of group B was significantly lower than group A,and the differences were statistically significant (all P<0.05).There were no significant differences in the other two groups.Conclusion:Atropine combined with penehyclidine in the treatment of severe AOPP were significantly better than the efficacy of atropine and penehyclindine alone,it can decrease the time of recovery of CHE activity to 70% and the length of hospital stay,reduce complications caused by atropine,improve the cure rate.