The 433 base pair segments of the mitochondrial cytochrome oxidaseⅠ(COⅠ) gene from 62 individuals of Frankliniella occidentalis (Pergande) and other 8 common thrips species in China were sequenced. The DNA data analysis showed that the average intra-species genetic distance was 0-0.005；there was no significant genetic divergence between the western flower thrips found in Beijing in 2003 and those reported internationally. The average interspecies genetic distance was 0.213. Thrips individuals of the same species were successfully clustered by NJ tree. The bootstrap values of the original divergence among intra-species haplotypes amounted to 100%. The results show that molecular identification based on PCR and direct sequencing is desirable for identifying thrips species.