Blended wing body (BWB) unmanned aerial vehicle (UAV) has good lift to drag and stealth characteristics, and has broad application prospects in both civil and military fields. In order to improve the endurance of the UAV, considering aerodynamic characteristic and structure weight requirement of blended wing body UAV, lift to drag radio and aircraft area are taken as optimization objectives, using Multi-objective optimization method to study configuration design of blended wing body UAV, putting forward a parameterized configuration optimization design method of UAV, and a practical example is given. The analysis results indicate that configuration optimization can increase lift to drag radio of UAV, reduce structure weight, and get an excellent design scheme of blended wing body UAV.