For the purpose of protection and utilization of Uroctea lesserti,the observation of its biological characteristics was conducted in the seashore area of Rizhao City,Shandong Province,from 1996 to 2003. The result shows that U.lessert reproduces one generation per year in Shandong Province,China.Hibernation occurs as larva within its self-made oblate sacks on walls or in caves and holes of bridges,emergence in early April the next year; imagines,mating,oviposition and hatching in early July.Its average incubation period is 13.5 days,larva period 337.2 days,and adult period 106.5 days.Its number ratio of male to female is 5∶3. It kills 5.8 gelechiid moth Mordv on average each day.Therefore it is an important natural enemy of various insect pests.It is very sensitive to chemical insecticide.Prohibition of chemical insecticide in rooms and forest is the key to protect the larva and adult U.lessert.