The phase I of the Eastern Route of the South-to-North Water Transfers Project (hereinafter referred to as Phase I) is an important part of the South-to-North Water Transfers Project and the backbone project of the national water network. Under the background of the current ecological civilization construction, the eco-environmental benefits of the receiving area of the project are widely concerned. Phase I has been in operation for nearly 10 years. As of the end of June 2023, a total of 6.139 billion m3 of water has been transferred to Shandong, which has brought remarkable benefits. So, scientific analysis of the eco-environmental evolution of phase I is conducive to the high-quality promotion of subsequent projects and the high-quality development of economy and society. To analyze the evolution characteristics of eco-environmental of the phase I, the role of phase I is analyzed in optimizing water resources allocation, ensuring drinking water safety for the masses, reviving the eco-environment of rivers and lakes, and smoothing the North-South economic cycle by combining qualitative and quantitative methods. The indicators, such as annual water supply, water quality improvement, ecological replenishment, groundwater pressure recovery, groundwater level, water area, green area, water conservation, were selected, and the eco-environmental benefit evaluation indicator system of the phase I was established. On this basis, the eco-environmental evolution analysis method of the phase I was established based on VIKOR compromise solution ranking method, considering the incongruity between multiple indicators. The constructed evaluation indicator system and evolution analysis method are applied to calculate and analyze the evolution situation of eco-environmental benefits of the phase I from 2013 to 2022. The results show that: The overall benefits have been gradually increasing since the opening of water supply, reaching a peak in 2020, and then basically stabilizing. The phase I has promoted the recovery of underground water pressure, water level, the pollution control and water quality protection along the route have also effectively improved the water quality of rivers and lakes, which have improved the eco-environment along the route. The phase I has produced sustained benefits in water resources protection and water ecological restoration, and is expected to achieve a steady equilibrium mechanism. The ranking value remained above 0.8 in the past three years; Affected by factors such as dry precipitation, which in turn affected groundwater extraction and groundwater level, indirect eco-environmental benefits decreased by 29.2% in 2019, and then quickly recovered and remained stable. Based on the analysis of the evolution of direct and indirect benefits, the corresponding improvement strategies are proposed from the aspects of improving quality and efficiency, ensuring water quality and evaluating mechanism construction, in order to provide references for eco-environment evaluation of the Eastern Route project and relevant research and decision-making on high-quality development. The constructed indicator system of eco-environmental of the phase I based on the analysis of the actual benefits from two dimensions of direct and indirect benefits is more targeted and operable. VIKOR method is adopted to analyze the evolutionary situation of eco-environmental of the phase I from 2013 to 2022, which can better clarify the main constraints of the improvement of eco-environmental in the current state. The eco-environmental of the phase I have basically shown a steady improvement since the water operation, but have declined to a certain extent after 2020. It should be pointed out that the improvement of the eco-environment along the phase I is the common result of the efforts of all parties under the background of ecological civilization construction and harmonious coexistence between human and nature. The water provided by the phase I is an important factor for the improvement of the eco-environment along the route, but it is not the only factor. When evaluating the ecological benefits of the phase I, how to clarify which eco-environment improvement is caused by the increase in water supply of the Eastern Route project, accurately calculate and analyze the ecological benefits of the phase I by selecting a reasonable indicator system, and evaluate and predict the development and change trend of the ecological benefits are difficulties worthy of further research and exploration.