Abstract: Nine species belonging to 9 families of insect pests of bamboo timber are recorded in Yunnan Province. Anobiidae and Curculionidae species harming to bamboo timber is reported for the first time. Dinoderus minutus, Dinoderus japonicus and Lyctus brunneus are the widely distributed and most harmful species. After the investigations of chemical composition and tissue structure of bamboo timber and the biology of insect pests, the authors have the conclusion that the rich contents in a large number of thin wall cells of bamboo tissue (about 45%~55%) is the main reason why bamboo timber being harmed easily by insect pests.