Studying and judging the impact of land use evolution on the ecosystem service value of national parks is an important basis for promoting the construction of ecological civilization system of national parks. In order to clarify the impact of land use evolution on ecosystem service value, based on the land use data of Sanjiangyuan National Park from 2000 to 2020, this paper first used the ecosystem service value correction model to calculate the ecosystem service value, and then used the value change rate model, GIS spatial analysis method to describe the spatial difference characteristics of the evolution of ecosystem service value of Sanjiangyuan National Park, finally, the cross sensitivity coefficient was introduced to reveal the impact trend of land use evolution of Sanjiangyuan National Park on ecosystem service value. The results show that:(1) in the past 20 years, the land use evolution of Sanjiangyuan National Park showed the mutual transformation among desert, grassland and water body, the time period with the largest rate of change was from 2015 to 2020, and concentrated in the northwest and north of the Yangtze River source park; (2) From the perspective of time series, the ecosystem service value of Sanjiangyuan National Park showed a trend of getting better, among them, the change from 2015 to 2020 was as high as 8.242 billion yuan, grassland and water bodies contributed greatly to the ecological environment of the park, there is a certain correlation between the evolution of land use types and ecosystem service value; (3) From the perspective of spatial evolution, the ecosystem service value of the three parks of Sanjiangyuan National Park (the source of the Yangtze River, the source of the Yellow River and the source of the Lancang River) from high to low is the source of the Yangtze River > the source of the Yellow River > the source of the Lancang River, showing the distribution characteristics of increasing from northwest to southeast; (4) The influence degree of land use type evolution on ecosystem service value was in the order of desert and water > grassland and water > desert and grassland. The larger the span of land use transformation, the stronger the impact on ecosystem service value. During the study period, the cross sensitivity coefficient of the impact of land use evolution on ecosystem service value showed the characteristics of first increasing and then decreasing, indicating that the change of ecosystem service value will also react on the sensitivity of land use to ecosystem service value.