Xiong'an New Area is a state-level development area established in 2017 and many buildings and roads have been developed in the area since then. Nevertheless, there were no researches on the ecological changes of the area caused by the development. To meet this requirement, two Landsat 8 images in 2017 and 2020 were selected in this paper to study the ecological effects of the areal development. The 2017 image was used to represent the period before the development of the Xiong'an New Area, whereas the 2020 image was to represent the period after three-year development. The development-induced main land cover changes in the Xiong'an New Area were revealed using remote sensing techniques. The remote sensing based ecological index (RSEI) was used to evaluate the ecological changes of the new area in the period due to the land cover changes. The results showed that (1) the development of the Xiong'an New Area from 2017 to 2020 has caused an increase of 60.01 km² in built-up land, an increase of 8.95 km² in open water, and a decrease of 69.29 km² in vegetation. The development of the new area is currently concentrated in Rongcheng and Xiongxian counties, while Anxin county is less developed. (2) The development-induced ecological change in the period is characterized by the fact that the ecologically improved area is larger than the degraded area, and the area proportion of remote sensing based ecological index (RSEI) above good grade rose slightly during the period. Therefore, the overall ecological quality of the new area has increased slightly in the three years, showing by the increase of the mean RSEI from 0.668 in 2017 to 0.677 in 2020. Nevertheless, the presentations of the three counties were different. The mean RSEIs of Xiongxian and Anxin counties have increased, while the mean RSEI of Rongcheng County has decreased slightly. (3) The improvement of ecological quality in the Xiong'an New Area mainly benefited from its new planning thought that insisted on ecological priority and green sustainable development, as well as the implementation of several projects to improve ecological quality, such as the Qian-nian-xiu-lin forest project and the returning of cultivated land to water project that insure high blue and green proportions in the new area.