Abstract: The characteristics of lac insect foraging behavior and its preference to host branch in foraging were studied.The results were as follow:when foraging,lac insects move forward,had no choice to moving way,seldom study foraging experience each other,and followed ESS strategy.The ratio of hosted branch below 1 year old was more than 95%,1 to 2 year old was 5%,Kerria lacca hardly hosted on branch over 2 year old.The distribution of lac insects on branches had no relation with orientation.The diameter of hosted branches ranged from 0.47 cm to 1.60 cm,and the ratio of these branches reaches 88%,which diameter ranged from 0.6～1.1 cm.On erect branches,lac insects distributed around the branch,but on most decline branches,lac insects only settled on shaded parts.Comparison anatomy results showed that:the periderm and cortex of 2 year old branch were thicker than that of 1 year old branch,and the layer of sclereids and fibres in 2 year old branch was thicker than that of 1 year old branch by 27 μm.The distance from periderm to phloem of 2 year old branch was farther than that of 1 year old branch.The periderm and cortex of upper parts were thinner than that of basic parts in the same branch.The phloem of sun shined parts was thinner than that of shaded parts in the same branch.Besides these,the keratinization of host tree suberin and tinsel on epiderm also inhibited lac insect foraging.