Wind power industry has developed rapidly in China, however the effect of wind power projects on ecosystem is far from clearly understood. The objective of the current study is to evaluate the negative impact of wind power plants on ecosystem. In this research, Least-cost distance (LCD) and Least-cost path (LCP) models were employed to establish potential ecological corridors based on the resistance at the site of the wind power projects, which is located in the ecological function area in Qinyuan, South Shanxi Province, China. Landscape connectivity was evaluated using a set of connectivity indices. In addition, the impacts on corridor patency, length and connectivity between ecological corridors were analyzed. The results showed that the wind power projects could not only significantly increase the migration resistance that hampers the formation of ecological corridors of the species at landscape scale, but also have an obvious cutting effect on the landscape, resulting in the increase in the length of the ecological corridors and the decrease in corridor patency and landscape connectivity. The average increased corridor length was 95 km. There was also a positive relationship between length increase and the distance between source patches. In addition, the connectivity was enhanced with the increase in distance threshold. This study evaluated the ecological impacts of onshore wind power projects at the landscape level, filling the gap in such research on landscape ecology, especially in the key ecological function protected area. Meanwhile, the results are beneficial to guide the selection of wind power projects location and minimize the negative impact on the key ecological corridors.