A systematic conservation planning method using irreplaceability (Ir) values of conservation planning units were calculated using C-plan software for northeast China.Four hotspot areas were identified,including the Changbai mountain area,northern Daxinganling mountain area,the transitional area between western grasslands and Daxinganling mountain forests,and the wetlands around the center of Songnen plain.Based on the results of the hotspot analysis,a GAP (Geographic Approach to Protect Biological Diversity) for biodiversity conservation was conducted in this region.The results showed that there are three evident protection gaps between the priority planning area and the existing national Nature Reserve.Based on our results,we provide suggestions for establishing new protected areas and eco-corridors in Northeast China.