In order to accurately estimate the working load in the actual state of air-thermal coupling and heat-structure finite element analysis, a multi-field coupling analysis method is proposed. This method first calculates the outer gas flow, inner cooling flow and blade solid heat transfer of the turbine blade to obtain the accurate temperature and aerodynamic distribution of the blade in the actual state, and then transfer the coupling load information to the heat-structure finite element model, and then realize the load multi-field coupling analysis through the heat-structure finite element analysis. The results of experimental data verification and example calculation show the effectiveness and accuracy of gas-thermal coupling and using load multi-field coupling analysis. Finally, the parameter sensitivity analysis quantitatively gives the degree of the uncertainty of each boundary condition affecting the coupling calculation.