Abstract: Due to the large number of randomly distributed dispersed particles in the matrix, the double heterogeneous (DH) system has a complex geometric structure, and it is often difficult to deal with the DH system using the traditional neutronics calculation method. The reactivity equivalent physical transformation (RPT) method is a commonly used approximation method. This paper analyzes the three key steps of the RPT method: the solution of the exact initial value, the solution of the equivalent radius, and the selection of the depletion algorithm. The influence of different algorithms on the efficiency and accuracy of the RPT method is discussed. Based on OpenMC, an RPT module is developed on the Python API. The numerical results show that the optimized RPT module can meet the needs of engineering calculation accuracy while maintaining good calculation efficiency.