This paper proposes a wireless power transfer (WPT) system with quasi-uniform magnetic coupling to satisfy the Unmanned Aerial Vehicle (UAV) lightweight constant current (CC) charging without secondary feedback control. The traditional wired charging for UAVs is less automated and not portable. WPT as a new way of energy supply has shown great potential for charging UAVs with safety and automation. However, some actual challenges still exist due to the UAV's special structure and lightweight requirements. Accordingly, a coupler with a lightweight receiving coil and double transmitting coils to satisfy the CC wireless charge of the UAV without communication and control is proposed in this article. The power transfer and CC charging theory analysis are carried out, and the structure of the coupler is designed. A simulation model and a prototype are built, as well as the simulation and experimental results are given to verify the performance of the proposed UAV CC charging system. In the experiment, 23.8 Wh of power is charged to the UAV's lithium battery pack with CC in two hours. this article provides a reference to the design of the UAV wireless charging stations.