By using simulation of a snowstorm in the Qinghai-Xizang Plateau, the precipitation error of the Weather Research and Forecasting (WRF) Single-Moment 3-class Microphysics scheme (WSM3) was analyzed. Observation and experiment results indicate that two modified schemes were used to calculate ice nuclei concentration. By adjusting the relationship between temperature and ice nuclei concentration in WSM3, the effects of the Pigen procedure on precipitation was validated; results show that WSM3 overestimates ice nuclei concentration. In addition, the simulation performance of precipitation can be improved by adjusting the relationship between ice nuclei concentration and ice surface saturation. However, the performance of precipitation simulation is not remarkable when both temperature and ice surface saturation are adjusted. Therefore, temperature has relationships with ice surface saturation and ice nuclei concentration. For solid precipitation with higher temperature, the two cases and sensitivity tests indicate that the effect of ice nuclei concentration on precipitation simulation is not significant.