Abstract: A four-rotor composite solar powered unmanned aerial vehicle（UAV） with a positive X-shaped body was designed. The aerodynamic characteristics, strength characteristics, and instability characteristics of each component of the UAV were analyzed using fluid-structure coupling method, and static tests of the carbon fiber rod were conducted using non-contact measurement method. The results show that carrying solar cells can effectively increase the stable hovering time of the UAV. Under the rated conditions, the load on the body does not change significantly with the flight angle, and when flying vertically, the load is concentrated in the central region of the UAV. The maximum climbing speed of the UAV is 4 m/s which is obtained through buckling analysis, and at this speed, the foam board, main beam, and solar cells all meet the strength requirements. The relative error between the simulation results and the static test results is 15%, which can meet the requirements of engineering design.