Abstract: To improve the endurance and payload capacity of emergency rescue UAV during operation, this study focuses on the design of an "X"-type quadrotor heavy-duty emergency rescue UAV. Using SolidWorks software, structural modeling and design were carried out for the frame, offset mechanism, payload release device, and lifting mechanism based on the design parameters. Additionally, component selection for the transmission system was completed. The results show that the designed UAV can achieve a continuous flight time of up to 4 hours and a maximum payload capacity of 160 kg. It supports multiple flight maneuvers including pitch, roll, yaw, and vertical take-off and landing, as well as essential functions such as long-distance wireless control. This study provides a strong reference for the structural optimization design of heavy-duty emergency rescue UAV.