With the Tanghe Diversion Channel in Tibet as an example, the theoretical study on the ice control effect of the solar sacks was conducted based on the previous study. The numerical simulation method was adopted and a one-dimensional numerical model for ice crystal in diversion channels in high-altitude cold regions was developed in this article. The heat transfer through the air-water interface and the mass transfer between ice and water were considered in the model. The model was validated by the field observation data on the diversion channel of the Tanghe Hydropower Station. The results show that the ice control effect of the solar sacks is obvious in the channel with large mass flow rate in the high-altitude cold regions.