Natural conditions have very important influence on the performance of the wind power generation system, especially high temperature environment will lead to device life reduction, and have a strong impact on wind power system reliability and life. The small wind power system main circuit loss is estimated and the model of which is built by ANSYS 12.1 experimental tools, the more accurate the main circuit of temperature field distribution are simulated by the mapping method, mesh discretization model, as well as some certain basis are provided for other parts of the simulation, so as to the circuit structure is better optimized and improved, and the small wind power system stability and reliability are enhanced.