According to the character that there are not enough realistic observed flood series in some rivers of Xinjiang and it is difficult for traditional statistic model to estimate flood risk, an information diffusion based fuzzy method is introduced to present a practical model for assessing storm-snowmelt flood risk in the Xindahe River of Akshu River Basin, with storm-snowmelt flood in the Xindahe River of Akshu River Basin as an example. The application results show that the model is reliable.