Aiming at the problems existing in the current use of agricultural water and land resources in China and in order to realize sustainable use of the two resources, we established an indicator system for comprehensive evaluation of agricultural water and land resources carrying capacity based on the Driving forces-Pressures-States-Impacts-Responses (DPSIR) concept framework. Then we took Sanjiang Plain as study area (including 6 cities and 1 county) and used projection pursuit (PP) model to evaluate regional agricultural water and land resources carrying capacity. The evaluation results indicated that seven indicators, including the arable wasteland rate, water resources utilization rate, urbanization rate, chemical fertilizer application in farmland per unit area, farmland irrigation rate, production GDP per unit water consumption and agricultural land output rate, were the key factors influencing agricultural water and land resources carrying capacity in Sanjiang Plain. Jiamusi, the main agricultural region of Sanjiang Plain, has the lowest carrying capacity of agricultural water and land resources. However, Muling has the highest carrying capacity. The evaluation results could provide scientific guidance for regional agricultural water and land resources sustainable use.