Abstract: The CLIGEN model (v5.22564) has been used to assess the precision of major precipitation parameters in the Neijiang city of the sichuan hilly basin based on interpolation-simple linear interpolation, Fourier series and a modified linear interpolation. The simulated results show that the rainfall days, rainfall probability of the event, the volume of rainfall et al., are reasonable. The results derived by non-interpolation method are closer to the real value compared with those derived by Fourier interpolation and linear interpolation, but the other values, such as the standard deviations for annual rainfall and seasonal rainfall and the extreme rainfall events, are lower than the real values. Because of the Sichuan hilly basin has been influenced by the southwest monsoon and the cyclones from the Qinghai-Tibetan plateau, the area has heavy rainfall intensity for summer days, while the CLIGEN model was established by using the climate data of the United States climate station, where the climate is characterized by medium and light rainfall intensity. This is the cause of the lower results for those parameters.