With the morphological characters, anatomy and molecular biology research, 29 entomopathogenic nematodes populations isolated from Gansu province were identified and the resoult showed that they were 8 species of EPN, Steinernema feltiae,Steinernema bicornutum,Steinernema affin,Steinernema krusse and Steinernema karil were belong to Steinernema while Heterorhabditis brevicaudis,Heterorhabditis megidi and Heterorhabditis marelatu were belong to Heterorhabditis respectively. And what more research found that S. affin,S. krusse,S. karil and H. marelatu were new species in China.