Abstract: Abstract: Soil erosion and ecological degradation are the most important ecological environment problems for the Chinese Loess Plateau in recent years, which have seriously hindered the sustainable development of the economy of the Chinese Loess Plateau. Based on the remote sensing image data of the Landsat TM and OLI, the remote sensing ecological index (RSEI) of the tableland protected regions of the Gansu, Shaanxi and Shanxi in the Chinese Loess Plateau were estimated during the period of 2002, 2009 and 2017 in this paper, and the influences of the change of the ecological restoration were also quantitatively evaluated. Besides, the locations of the regions of main ecological degradation were also screened out in this study. The results show that: (1) compared with the results of 2002, the remote sensing ecological index of the Gansu tableland region in 2017 showed a slightly increasing trend (increased by 0.04). Besides, the RSEI of the Shaanxi tableland region in 2017 also showed an obviously increasing trend, and the RSEI increased from 0.45 (in 2002) to 0.56 (in 2017), which indicated that the ecological environment of the Shaanxi tableland region has been improved. The RSEI of the Shanxi tableland region decreased from 0.54 (in 2002) to 0.46 (in 2017), which indicated that the ecological environment of this region has been degraded. (2) Compared the results of 2017 with 2002, the areas of the poor ecological conditions and relatively poor ecological conditions in the Gansu tableland region reduced obviously, while the areas of the good and excellent ecological conditions showed an increasing trend. In the Shaanxi tableland region, the areas of the poor ecological conditions and the relatively poor ecological conditions also demonstrated a decreasing trend, while the areas of the medium ecological conditions and the good ecological conditions increased significantly, the excellent areas presented a fairly stable status. In the Shanxi tableland region, the areas of the poor ecological conditions, the relatively poor ecological conditions and the medium ecological conditions presented increasing trend, while the areas of the good ecological conditions and the excellent ecological conditions showed a decreasing trend. (3) In the Gansu tableland region, the degradation of ecological environment mainly located in the Puhe and the Honghe river basins. In the Shaanxi tableland region, the degradation of ecological environment mainly distributed in the Juhe, Sanshuihe, Ganhe and Qishuihe river basins. In the Shanxi tableland region, the ecological environment degradation areas concentrically located in the Zhouchuanhe and Ehe river basin. (4) Compared the three tableland regions, the ecological conditions in the Gansu tableland regions and the Shaanxi tableland region have been remarkable improved during the period of 2002-2017. Although the ecological conditions in the Shanxi tableland region have declined, the improvement trend of ecological conditions has emerged in this study area. With the continuous implementation of various soil and water conservation and ecological restoration measures, the ecological environment in these three tableland regions of the Chinese Loess Plateau will be effectively improved. The research results of remote sensing ecological security in this paper have a far-reaching significance for the ecological restoration of the tableland regions of the Chinese Loess Plateau, and it is informative for the comprehensive control of regional soil erosion.