As one of the largest investment and extensive ecological restoration and conservation projects in China, the ecological and socioeconomic effects of the Grain for Green Project are the hotspots of policy makers, managers and academics. In this paper, the areas of cropland transferred to forest or grassland, vegetation coverage and soil erosion amount were selected as indicators. The regional characters of ecosystem changes due to the project from 2000 to 2015 were analyzed. The macro ecological effects of the project were evaluated based on the project planning objectives. The results showed that (1) in the past 15 years, the areas of cropland transferred to forest and grassland were 12.75×10⁴ km² and 9.43×10⁴ km² respectively, mainly occurred in the hilly-gully region of the Loess Plateau, the mountain and sand area in Northeastern China, the arid and semiarid regions in Northern China, and Yunnan-Guizhou Plateau. (2) The average annual vegetation coverage increased by 0.17% in the project region, of which the vegetation coverage increased by 0.32% in the area of cropland transferred to forest and by 0.43% in the area of cropland transferred to grassland. It was obviously in the hilly-gully region of the Loess Plateau, the arid and semiarid regions in Northern China, and the arid desert regions in Xinjiang. (3) The average annual modulus of soil water and wind erosion decreased by 0.13 t/hm² and 0.68 t/hm² in the project region, respectively. In which, it decreased by 0.43 t/hm² and 0.21 t/hm² in the area of cropland transferred to forest, and decreased by 0.55 t/hm² and 0.94 t/hm² in the area of cropland transferred to grassland, respectively. It was also apparent in the hilly-gully region of the Loess Plateau, Yunnan-Guizhou Plateau, the hilly regions in Sichuan, Chongqing, Hubei and Hunan Provinces, and alpine canyon regions in Southwestern China. (4) Compared the remote sensing estimation with the project planning objects, the implementation rate of area for returning cropland to forest reached to 87%. The vegetation coverage of forest and grassland in the project region increased by 4.8%-6.5%. The average modulus of soil water and wind erosion in the project regions decreased year by year, and the proportion of sloping cropland over 15 degrees returning to forest or grassland exceed 50% in most counties. The positive effects of project on vegetation coverage and soil erosion resistance has been highlighted in the Loess Plateau, mountain and sand area in Northeastern China, and Yunnan-Guizhou Plateau.