Abstract. In the research of route planning, better balance between planning time and route quality should be achieved to reduce UAVs cost. This article is based on basic RRT (Rapidly-exploring Random Trees) and proposes an improved RRT_Connect algorithm which improves the way generating new node of the tree, and changes the parameters by the fuzzy inference according to the circumstance. Simulation and experiments prove that the improved RRT_Connect algorithm improves the efficiency of the planning and optimizes the route.