[Objective] A simulation model of the multi-source joint allocation for the Hanjiang to Weihe River water transfer project and Heihe River diversion project of Shaanxi Province was established. This was aimed at providing a basis for the sustainable development of water resources in Xi'an City.[Methods] Based on the analysis of the water supply project and the consumers of water in Xi'an City, the mixing rule was determined. This was achieved by constructing a network generalization map of the system of water resources and by building a simulation model of the multi-source joint allocation. Through a long series of calculations, the joint deployment scheme for different water supply frequencies was obtained.[Results] In 2020, when the incoming water frequency will be 50%, 75% and 95% respectively, the water supply of the Hanjiang River will be 39.74%, 37.59% and 35.33%, respectively. In the special dry year, the water supply of the Hanjiang River was 1.19×10⁸ m³, accounting for 36.28% of the total water demand in Xi'an City.[Conclusion] The water shortage in Xi'an City can be effectively alleviated by the implementation of the water diversion project, which has played a significant role in ensuring the safety of the water supply in Xi'an City.