Conflict between limited water supply and the ever-increasing water demand poses the challenge of synergetic management of agricultural water and land resources (AWLR). Sustainable development strategy and changing environment increase the multi-dimensional characteristic and complexity of the management of AWLR. This paper establishes a model framework for the multi-dimensional optimization of AWLR in a changing environment. The model framework is advantageous of: (1) Comprehensively allocating water and land resources on the basis of clarifying their interactions; (2) Balancing incompatible goals from multiple dimensions including resources, society, economy, ecology, and environment; (3) proposing alternative allocation schemes of AWLR that can response to the changing environment of both natural and socio-economic changes. Allocation schemes of AWLR based on the model framework are generated, analyzed and evaluated. The comprehensiveness, equilibrium, and security of multi-dimensional targets help obtain the optimum adaptation allocation plans of AWLR to cope with changing environment. The real-world case study in Songhua River Basin in Northeast China verifies the feasibility and practicality of the model framework. The study found that the model framework can manage AWLR in a sustainable way and meanwhile provide decision makers alternatives plans of AWLR for different natural and social changing environments, which will further contribute to the alleviation of agricultural water scarcity and the promotion of agricultural sustainable development.