Abstract: The horntail Sirex rufi-abdomins Xiao et Wu is a new insect pest seriously damage to Pinus massoniana Lamb found recently at Chu Xian county,Anhui province.It has one generation per year and overwinters as larva in the sapwood.In the late March next year,the larvae eat sapwood.Pupation takes place in August and September,and the adults emerge in Septmber and October.The eggs are laid in the sapwood.The pine trees injured are gradually dead.The larval stage lasts more than ten months,and pupal stage 17 to 20 days and egg stage 21 to 24 days,and adult stage 5 to 15 days. The most effective control method is keeping the stand in a sanitary condition and cutting the dead trees before summer and handling them as quickly as possible.