Abstract: Thanasimus dubius(Col.: Cleridae) is one of the main natural enemies of many bark beetles,and shows an essential natural control to the beetle population.The present paper studied the predation of Thanasimus dubius on Tomicus piniperda(Col.: Scolytidae) adults,as well as influences of the clerid predation on the bark beetle reproduction processes and reproduction rate.At room temperature of 22～24 ℃,one clerid female adult may averagely feed on 0.61 bark beetle adults(SE=±0.043) a day.In the laboratory,we placed the clerid adults into Yunnan pine(Pinus yunnanensis) logs in which T.piniperda adults have been introduced.The result showed that,Thanasimus dubius adults can interfere reproduction processes of the beetle,causing the decreasing of the beetle reproduction rate.Thanasimus dubius larvae preyed all young stages of the beetle inside logs,recorded predation rate of 8.3%.In the field,we placed Thanasimus dubius adults on the stems of the damaged Yunnan pine trees and then covered the stems with nylon screen.This study demonstrated that the clerid preyed 10.6% of larvae and pupae of Tomicus piniperda living beneath the bark.The present study indicated that Thanasimus dubius may influence Tomicus piniperda reproduction through three aspects at least,feeding on the bark beetle adults,interfering the reproduction processes of the bark beetle,as well as preying the beetle larvae and pupae,and was so regarded to play a substantial role in control of Tomicus piniperda population.