Abstract: Based on the test of effectiveness of killing pests in logs and the gas components produced by this treatment,as well as the variation of DO in water where the logs were stored by using water soaking treatment,we conclude that the principle of killing the pests is as follows:the organic oxidation under a certain temperature consumes DO and oxygen in the insect holes that can cause the death of the pests by suffocation,and also the oxidation can produce a large quantity of toxic gases(H 2S,SO 2,CO, et al .)which can enter the insect holes and the tissues that contribute to the death of the pests.The results indicate that the water soaking treatment can reach the aim of quarantine for killing the pests.