Laser interferometry is used in the Taiji program to detect gravitational waves ranging from 0.1 mHz to 1 Hz, and picometer-level ranging accuracy needs to be achieved. Limited by the interference of ground environment and the length of ground test baseline, it is difficult to carry out the experimental verification of key technologies and indicators on the ground. Therefore, implementing a computer simulation based on detection principles is crucial. The simulation method of combining the geometric and wave optics is adopted, and corresponding models, including the Gaussian beam and its propagation model, diffraction model, telescope model, and readout signal model are implemented and validated by comparing with analytical methods and other simulator. Afterward, the intersatellite laser interference link based on split interferometry detection applied by the Taiji program is simulated. The results are verified by theoretical analysis. This work can provide a foundation for the simulator development and further be applied in the optimal design of interferometer for the Taiji program.