A transformer thermal fluid field mesh optimization generation method based on the calculation results difference feedback is proposed. The number of meshes obtained by the local mesh refinement optimization based on the difference distribution feedback of results is 1.972 million, which is reduced to 72.7% of the number of meshes obtained based on the global refinement method. A temperature rise test platform is built in which the windings have embedded optical fiber temperature measurement system, and based on the test results under rated condition, the absolute errors between the calculated hot spots of HV and LV windings and the test values are 0.81% and 0.40%, respectively, which verify the effectiveness of the method. The thermal fluid field calculation mesh optimization generation method can reduce the number of calculation meshes while ensuring the calculation accuracy, and can provide a reference for mesh optimization control in transformer thermal fluid field calculation.