In order to meet the diversified needs of thermal analysis of fuel tank in the development process of civil aircraft fuel system and inerting system, the lumped parameter method is used to establish the thermal model of a typical narrow trunk airliner fuel tank by using Matlab / Simulink software. By modeling and optimizing part of the convective heat transfer process, and integrating the actual engineering data into each calculation link, the simulation error of the thermal model for the main tank is less than ± 2 ℃ after checking and correcting the flight test data. The application of fuel tank thermal model in civil aircraft development was demonstrated through the analysis of fuel icing conditions, such as fuel system thermal climate flight test analysis, and the analysis of the influence of fuel tank configuration differences on fuel temperature, and the typical engineering application of fuel tank thermal model in civil aircraft development was presented. In order to further improve the generality and ease of use of thermal model, combined with engineering experience, through key input parameterization, integrated flight parameter automatic generation module and fuel allocation calculation module, an engineering application type fuel tank thermal analysis tool with independent operation interface is formed, which provides a reference for the efficient engineering application of civil aircraft fuel tank thermal model.