Thermal model analysis of the fuel tank is a key technology of the aircraft fuel system design and airworthiness certification. In this article,the fuel tank thermal model analysis method was clarified firstly,then investigated the thermal parameters of a typical civil aircraft fuel tank structure by engineering calculations in a typical hot day environment (ground temperature is 327K),studies show that the fuel temperature in the wing tank,fuselage tank and collector tank are varied. The temperature of the ground state is higher than the cruise. The maximum temperature reached in the end of ground state,and the highest point appeared in the collector tank. The results can both guide the design of aircraft fuel tanks and provide some technical support for airworthiness.