Qinghai Province is chosen as the study area, and its eight administrative districts are regarded as the study units. By using the fuzzy matter-element analysis method based on the combination weights, the evaluation index system of “Three Red Lines” for the carrying capacity of water resources in Qinghai Province is established from the dimensions of the total water use, water use efficiency and water quality. The results show that the water resources in Qinghai Province have great potential for development, and their carrying capacity is strong. However, the development conditions and utilization degrees of the water resources in Qinghai Province exhibit regional differences. The carrying capacities of water resources in Xining and Haidong cities have reached their limit values, and those in other regions are relatively stronger. It's necessary to take appropriate measures in accordance with the local conditions.