Abstract: Diversity of bacteria,isolation and identification of chlorpyrifos-degradating strains on the phyllosphere of Brassica chinensis were studied in the paper. The bacteria on the phyllosphere of Brassica chinensis were seperated by LB culture medium,PDA culture medium,high one medium and inorganic salt medium contained 100 mg/L chlorpyrifos,and their number of bacteria were 1.24×10⁶,1.03×10⁴,2.07×10⁴ and 2.64×10⁵ CFU/g respevtively,which showed the diversity of bacteria number. There were 51 strains of bacteria with obviously phenotype were selected. Their dominant bacterias on each medium were Enterobacter(28.0%),Enterobacter(75.0%),Arthrobacter(100.0%)and Pseudomonas(55.0%)by identification of 16S rDNA with PCR respectively. Their degradation rate of chlorpyrifos were determined by QuEChERS-GC/MS,and 11 strains were isolated with good degradation activities to chlorpyrifos. The maximum rate of chlorpyrifos degradation was 52.44%,the strain was Serratia ureilytica M1.This study found that diversity of bacteria which was isolated and identified from phyllosphere of Brassica chinensis by various culture medium was obviously different,and chlorpyrifos-highly-degradating strains were also isolated and identified from phyllosphere of Brassica chinensis,which provided a basis for the study of degradation characteristics,application and mechanism of chlorpyrifos-degradating strains.