The experiments were conducted to determine the debilitation effect of Spodoptera litura nucleopolyhedrovirus (SlNPV) on hosts from the infected parental generation to their next two progenies through feeding the larvae with the concentration of 9.44×107 OB/mL and the adults with the concentrations of 9.44×108 OB/mL and 9.44×107 OB/mL in the laboratory. The experiment results of feeding the early 4th-6th instar larvae with SlNPV in concentration of 9.44×107 OB/mL indicated that the pupation rates of F1 and F2 progeny were respectively reduced by 12.73%-18.59%, 5.88%-10.21%, and the emergence rates went down respectively done by 11.31%-15.41%, 5.70%-8.46%. The experiment results of feeding the adults with SlNPV in concentrations of 9.44×108 OB/mL and 9.44×107 OB/mL showed that the pupation rates of F1 and F2 progeny were respectively reduced by 14.00%-34.63%, 8.33%-9.84%, and emergence rates were respectively decreased by 10.77%-19.61%, 11.36%-12.00%. After feeding the early 4th-5th instar larvae and adults with SlNPV,pupal weight and fecundity of F1 and F2 progeny were both significantly decreased, oviposition period and adult longevity were both significantly shortened,but there were was no significantly difference in larval duration, pupal stage and preoviposition period between F1 and F2 progeny. The results also indicated that the debilitation effect of SlNPV on host was weakened gradually with the increase of host progeny.