Objective  The Songnen Plain is an important ecological function area in northeastern China. Due to increased human disturbance, the wetland area of the Songnen Plain has shrunk significantly, wetland functions have degraded, water quality has deteriorated, and biodiversity has decreased. In addition, the limitations of the management system and the fragmentation of the geographical space of the established nature reserves at all levels and types also lead to the problems of habitat isolation and fragmentation. Therefore, the Songnen Plain urgently needs to integrate and optimize various protected areas through establishing the national park, which can provide a solid foundation for sustainable development and promote the construction of regional ecological civilization.

  Method  This paper puts forward a set of methods for comprehensively drawing up the appropriate range of national parks. Firstly, the indexes of ecosystem integrity, natural background authenticity and management feasibility were calculated, respectively. Then, the normalized superposition analysis index was carried out, and the natural breakpoint method was used to divide the analysis results to draw up the appropriate scope of the national park. Finally, the boundary of the proposed Songnen Plain National Park was determined according to the appropriate area, connectivity between areas and field investigation.

  Result  Ecosystem integrity evaluation results showed that the integrity of the wetland ecosystem in the area was the highest, the natural authenticity evaluation results showed that the authenticity of the area was overall low, the results of management feasibility evaluation showed that the feasibility index of the space where the original National Nature Reserve located was high.

  Conclusion  Songnen Plain National Park is proposed to be established, which is based on the original 6 national nature reserves of Zalong, Wuyuer River, Xianghai, Momoge, Tumuji and Horqin. The Nenjiang River and wetlands on both sides connect Zalong and Momoge, and the boundary delimitation scheme divided into 4 areas is more appropriate.