Abstract: The demand for organochlorine pesticide (OCP) determination in soil samples has been increasing rapidly in recent years. According to the previous standard methods and the requirements of laboratory measurement for batch samples, systematic experimental studies were carried out on each step of the sample pretreatment and instrumental analysis starting from eliminating background interference and improving data quality. Therefore, the analytical method of OCPs in soils by GC/MS was comprehensively optimized. All analytical procedures were monitored using strict quality assurance and quality control measures including control of inlet degradation of DDT, sound selection of qualitative and quantitative ions for OCPs, and the usage of Standard Reference Materials. The results suggest that recoveries of the 22 OCPs on the clean matrix spiked test ranged from 70% to 110%, and the method detection limits ranged from 0.0325 to 0.4450 ng/g.