The mismatch of water and land resources leads to various water problem and degradation of ecological function in the basin. The existing water resources allocation and land resource allocation have different objects, basic units, allocation goals and methods, and it is difficult to achieve joint allocation on a unified platform. This paper takes the water and land resources system as the research object. The optimal allocation model of water and land resources was constructed, with the multiple objectives, from aspects of water quantity, water quality, water efficiency, ecological function and the matching degree of water and land resources. The constructed model is used to allocate water and land resources in Sihe River basin, and the results of water and land resources allocation of each configuration unit under different water supply conditions are obtained. This provides technical support for the synthetically delicacy management of water and land resources based on the land unit in the river basin.