This experiment was conducted to investigate pathogenicity of Spodoptera litura nucleopolyhedrovirus (SINPV) with different temperatures to mass production. In laboratory, LC$_{50}$ values of SINPV were 5.534$ imes$10$^3$ PIBs/ml and 4.l0$ imes$10$^2$PIBs/ml in 1st instar larvae at 2$0^{circ}C$ and 28$^{circ}C$, respectively, but those were increased at 32$^{circ}C$. LC$_{50}$ at 3rd and 5th instar larvae were showed the lowest value at 28$^{circ}C$. LT$_{50}$ values of SINPV in 1.0$ imes$10$^{5.7}$ PIBs/ml were determined at various temperature conditions (20-32$^{circ}C$). The result showed that treatments at 28$^{circ}C$ and 32$^{circ}C$ shortened LT$_{50}$ values, but treatments at 2$0^{circ}C$ and 24$^{circ}C$ was relatively longer. Also LT$_{50}$ values was shortened in high concentration and young larva. LT$_{50}$ values are dependent on the temperature, viral concentration and larval instar.