Aiming at the difficulties of regional multi-source and multi-user water resource allocation, the water intake space-time adaptation algorithm(WISAA) was proposed based on actual water supply and usage characteristics and dynamic industry water demand. The water supply process calculation module of the water allocation and simulation (WAS) model was improved and applied to Ezhou City, Hubei Province to verify the improvement effect of WISAA. The results show that the relative error of the modified WAS model for water supply of different water sources and different industries is less than 2%, and WISAA can effectively address the difficulties of water supply changes and unstable water distribution calculation processes during multisource periods, making the water supply process more robust throughout the year. When the water distribution ratio coefficient in the industry is less than 0.6, the average absolute percentage error of the annual water supply simulation results of modified WAS model is less than 5%, and the optimization effect of WISAA is more significant.