Purpose: To explore the influencing factors of cholinesterase activity in omethoate-exposed population and screen susceptible people.Methods:To detect the cholinesterase activities in whole blood, red blood cell and plasma using the methods of GBZ52-2002 appendix B;Genetic Polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)method, and real-time PCR method was applied to determine gene expression levels.Results: The cholinesterase activities of whole blood, red blood cells and plasma in exposure group were lower than those of the control group, the differences had statistical significance (P < 0.001);the mRNA expression levels of p53 and p21 in exposure group were significantly lower than those of the control group (Z=12.137,P<0.001;Z=5.358, P<0.001);Multivariate analysis found that group (b=-1.109,P<0.001), gender (b=0.379, P<0.001), alcohol (b=0.228, P=0.027) andp53 rs17878362 (b=-0.400, P=0.048) had an impact on cholinesterase activities;However,smoking, age, working duration and other genetic polymorphisms were not found to have impacts on it (P>0.05).Conclusions: The whole blood, RBC and plasma cholinesterase activities in exposure group were lower than those of the control group,and the main influencing factors were omethoate-exposure, gender, age, alcohol and p53 rs 17878362 polymorphism;moreover, the cholinesterase activities of LL+SL genotypes individuals for p53 rs 17878362 genetic polymorphism were significantly lower than those of SS genotype, suggesting that SS genotype may be the protective factor of cholinesterase.