To solve the problem of logistics UAV transportation path planning in low-altitude environment, considering the internal and external constraints of low-altitude planning airspace and physical performance, an improved A* algorithm is designed to plan the path quickly. To apply the method to the transportation for logistics UAV, the algorithm uses the grid method to model the environment. It also introduces grid’s danger rate and the cost of flight time and energy consumption in the cost function. At the same time, the dynamic weighting method is applied to estimate the function. The simulation results show that the algorithm can plan the obstacle-avoidance transportation paths with low risk and low energy consumption quickly under the constraints of the assumed environment and UAV performances. Also, its performance is superior to the original algorithm and ant colony algorithm. Meanwhile, the corresponding grid length and weight value of the optimized path are obtained, and the effectiveness of the algorithm is verified.