The disunity of model structure and parameter of existing power system commercial software makes the existence of a large amount of heterogeneous data sources and the difficulty of data exchange between software. To solve this problem, a model parameter conversion method based on improved genetic algorithm (IGA) is proposed. By analyzing the differences of model structure and parameter design, model parameter conversion between power system software is realized. Parameter conversion of dynamic model in PSASP based on IGA method is done during the import process of BPA simulation data of IEEE 39-bus system example into PSASP. Simulation calculation is conducted using the conversion result, whose result is consistent with that of BPA simulation. The consistence verifies the effectiveness of parameter conversion of dynamic model in power system simulation software using the proposed method which in addition improves the accuracy of data exchange between power system simulation software.