The reproduction, extraction, pathogenicity to Tea Tussork Moth and electron micrograph testing of Euproctis pseudoconspersa Nuclear Polyhedrosis Virus(EpNPV) was investigated. The EpNPV was propagated through Inoculating 2~3 instar larvae of Euproctis pseudoconspersa, by raged with EpNPV at the concentration 10⁶βPIB/ml, or inoculating 2~3 instar larvae in field condition. Inoculation the larvae with 10⁶βPIB/ml, 10⁷βPIB/ml, and 10⁸βPIB/ml of EpNPV, the corrected mortalities were 43.60％, 76.13％ and 64.68％ on day 12 respectively, and reached 59.17％, 95.71％, and 95.70％ on day 14 respectively. The mortality was 78.11% on day 15 treated with EpNPV(10⁷βPIB/ml) under field condition. Virus of the EpNPV from the field dead larvae could be watched through the electron microscope.