Abstract: Aiming at the problems of spatial mismatch of water and land resources, lack of total water resources and low utilization of land resources, this paper establishes a joint optimal allocation model of regional water and land resources considering mutual feedback relationship based on the dualistic water cycle theory. This model consists of water production module, water and land resources joint allocation module and land simulation module, and takes maximum GDP and maximum regional vegetation coverage based on ecological green equivalent (EGE-RVC) as the objective functions. A three-layer nested algorithm coupling constraint method (CSM), successive approximation (SA) method and nonlinear programming (NLP) is proposed to solve the model. The proposed model and method are validated by taking Luoyang City of Henan Province as a research example. The results show that the available water volume in Luoyang City increases by 4 463 million m³, the GDP increases by 12.5%, and the EGE-RVC increases by 2.6%. The water shortage rate of each land type has decreased to varying degrees. The research results can provide a new idea and technical reference for the research on the optimal allocation of regional water and land resources.