Abstract: Choice experiment and bioassay were conducted in the laboratory to identifiey the mechanism of induced resistance of Populus deltoides after Clostera anachoreta feeding. Its effect on the host preference and growing development of the insect herbivore was studied. The result showed that larvae prefer to healthy leaves under choice situation. After feeding on treated leaves, the larvae development time prolonged, mortality rate increased greatly, the relative growth rate (RGR) reduced significantly, the efficiency of conversion of digested food (ECD), the efficiency of ingested food (ECI) and relative consumption rate (RCR) decreased although no significant difference between treated leaves and healthy leaves. Furthermore, the development of pupae and adults were also affected negatively after C.anachoreta feeding on treated leaves, and pupae weight declined, emergency rate and number of egg laying decreased. This study indicates that insect herbivore can elicit P.deltoides induced resistance which inhibits nutrient metabolism and retards the behavior and development of C.anachoreta.