Abstract: The biology analysis on EPNs of Steinernema longicaudum BPS strain, isolated from the oak tree soil near Sheng Quan nunnery in Pinggu district of Beijing, China, was studied to understand the potential of being bio-control agent. The results shown that after 72h infection at 25℃, BPS had similar effectivity to infect hosts at the dosages of 10 and 20IJs/larva. The proofreaded mortality (PM) of Galleria mellonella and Tenebrio molitor was 40.0%, 36.7% and 50.0%, 53.3%, respectively. The ability of BPS infection at the dosages of 40, 80 and 160 IJs/larva was increased while the dosages were raised up. The PM of G. mellonella and T. molitor was 73.3%, 86.7%, 90.0% and 70.0%, 80.0%, 90.0%, respectively. BPS infection at the dosages of 320 and 640 IJs/larva had same effect (100% PM) to both hosts. The heat tolerance of BPS at 40℃ for 1h and 3h, the PM was 98% and 100%, respectively. It was 92.4%, 55.4% and 45.7%, respectively at 37, 36 and 34℃ for 10h, and 100% for 20h. BPS ability of transverse diffusion at 30℃ was better than that at 18℃ and 25℃. There was 34.6% individuals could move 3.6 cm in 24h at 30℃.The results indicated that BPS had good capacity of host infection, heat tolerance and transverse diffusion. Hereby, it was concluded that BPS has the potential to development and application.