Inner Mongolia grassland is an important ecological protection barrier in China and part of it is the important agro-pastoral ecotone, but it is dry and windy, with fragile surface material structure, strong soil erosion, and extremely fragile ecological environment. Located in the mid-eastern Inner Mongolia grassland, Xilin Gol Grassland is a typical temperate grassland. In-depth research on the impact of returning farmland to grassland on the gross primary productivity (GPP) of land vegetation in Xilin Gol Grassland and related environmental factors is of great significance to understand the regional vegetation growth status and biological carbon sequestration capacity in the project of returning farmland to grassland as well as to formulate scientific policies for returning farmland to grassland. We use the VI model to estimate the GPP change in the Xilingol Grassland Conversion Area from 2010 to 2015. Based on MODIS remote sensing data, ground observation data, environmental factor data and land use data, this paper systematically studied the characteristics of the GPP change of land vegetation in the area of returning farmland to grassland in Xilin Gol Grassland from 2010 to 2015 by using residual analysis, correlation analysis and partial correlation analysis, and discussed the impact of different environmental factors on the GPP change, and revealed the characteristics of the GPP change and the active mechanism of environmental factors after returning farmland to grassland. The results showed that: (1) the average GPP change in the area of returning farmland to grassland in Xilin Gol League within 5 years was 0.47 g C/m², in which the area with an increased GPP accounted for 67.2% of the total area of returning farmland to grassland, and the GPP change in the initial stage of returning farmland to grassland was not significant; (2) In the area of returning farmland to grassland, soil water content and soil organic carbon were significantly negatively correlated with the GPP change, while air temperature, precipitation, elevation, and slope were significantly positively correlated with the GPP change, and there is no significant correlation between soil nitrogen content, soil phosphorus content, and soil potassium content with GPP change; (3) Slope and soil water content had the strongest correlation with the GPP change, and had a higher impact on the GPP change after returning farmland to grassland,precipitation and oil organic carbon had the strongest correlation with the GPP change, environmental conditions have a significant impact on the GPP change after returning farmland to grassland.