Based on set-pair analysis theory and triangular fuzzy number theory, the state evaluation model of water resources carrying capacity was established. Through theoretical analysis, frequency calculation and data statistics, 14 indexes were selected, and each index was divided into five grades, to establish an evaluation index system of water resources carrying capacity. The weight of each index was calculated by means of combination of subjective and objective weights, and the main influencing factors and reasons of water resources carrying capacity were analyzed. Based on the connection number method, the situation of water resources carrying capacity of each sample was analyzed by set-pair subtractive situation. With the data of 17 cities in Shandong Province in 2015, the results were analyzed. The results show that: main factors that affect the water resources carrying capacity of all cities in Shandong are irrigation water per unit area, groundwater resources per unit area and wastewater discharge per unit area. From four characteristic layers, the weight of natural characteristics of water resources is the largest. The overall carrying capacity of water resources in Shandong is in the state of critical overloading and slight overloading. Under the condition of stable water resources, improving water resources utilization efficiency and improving water environment can effectively improve the carrying capacity of water resources. Through the analysis of examples, the model is practical and effective, and has certain practical significance and value.