Abstract: Steinernema sp. (isolation No.CB-2Y) was isolated from the soil of an apple orchard in Hebei Province in 1986. laboratory experiments demonstrated that CB-2Y could infect its insect host and reproduce under 15-30℃. The optimal temperature for its in-vitro propagation was found to be 20-25℃. the nematode remained its infectivity in sandy soils with 10-17% water content. In the soils with less than 7.5% water content, the nematode could survive without infectivity. It died when the soil water content was below 2.5%. CB-2Y maintained infectivity for 16 weeks in sandy loam with 14.5% water content at 23℃, while Steinernema feltiae agriotos only kept its infectivity for 4 weeks under the same condition. The new nematode strain also showed a strong vertical dispersal ability, 57% of the experimental population dispersed to 5 cm deep in the sandy soil in 3 days, with the maximum dispersal distance of 30 cm. Results of the ou.tdoor experiments showed that CB-2Y could overwinter in Beijing area. In the soil of 25-30 cm deep, the overwintering survival rate was found to be 47.8% after 4 months.