The poverty alleviation relocation is a special poverty alleviation project for the poor people who live in the regions with bad soil and water conditions which can't afford to their lifestyle. The project is not only possible for poor people to get rid of poverty, but it also contributes to improve the ecological environment in the ecologically fragile regions. During the 13th Five-Year Plan period of China, the population relocated from inhospitable areas in Guizhou province accounted for about 1/5 of the total population in China. As a result, Guizhou province has the largest population of under relocated people from inhospitable regions in China.Thus, this study takes a county with the largest relocated population in Guizhou province as an example. Based on land used maps in 2009, 2015 and 2020 years and spatial data of poverty relocated population, a modified equivalent factor method and a coupling coordination model were used to explore the relocation of the largest population in Ceheng County, Guizhou Province. Meanwhile, the Spatial-temporal evolution of ecosystem service value (ESV) with the implementation of the policies for poverty-alleviating relocation out of inhospitable regions and its intrinsic laws were analyzed, and then the effectiveness of poverty alleviation relocation for ecological restoration were explored. The experimental results show that:(1) From 2015 to 2020 after the project implementation, the ESV has a significant improvement, which is increased by RMB 832 million yuan at a rate of 17.97%, more than 4 times that from 2010 to 2015 before the implementation of the project at a rate of 4.13%; and (2) In the study area, the growth of ESV of the six towns of Pomei, Sandu, Qiaoma, Yata, Badu and Baikou accounts for 82.89% of the total increment of the study area, which is the largest contribution of the ESV increment; and (3) There was an obvious spatial correlation between the poverty-alleviating relocation out of inhospitable regions and the growth of ESV, and the coupling coordination degree between the ESV variable and the relocated population's density in this study area was significant association. The larger the relocation of the townships in the county, the more obvious the increase of ESV. From the perspective of ecosystem services, this study quantifies the effects of ecological restoration triggered by the poverty-alleviating relocation out of inhospitable regions. The results of this study are helpful for improving the scientific and spatial pertinence of the corresponding follow-up work.