The broad-leaved Korean pine (Pinus koraiensis) mixed forest (BKPF) is one of most biodiverse zonal communities in the North Temperate Zone. Changbai Mountain in northeastern China contains one of the largest BKPFs in the region. The national government has established a network of 24 nature reserves to protect the BKPF and its vital species. So far, however, these reserves have performed with low efficiency. This paper attempts to optimize the conservation network. It proposes utilizing conservation planning software C-Plan to calculate the irreplaceability value (Ir) of each planning unit and identify high conservation value (HCV) gap areas. The overall goal of this approach was to assess the efficiency and comprehensiveness of the existing conservation network in supporting species biodiversity in the BKPF. The study also identifies specific gap areas that could optimize the network's protection capability if they were integrated into the network. The results show a number of HCV planning units concentrated along certain ridges. The habitats of 24 species (out of a total of 75) achieved their identified conservation targets in the existing conservation network. The other 51 species did not achieve the conservation target, and the habitats of 20 of these 51 species achieved less than 50% of their conservation targets. This low conservation efficiency can be greatly optimized by including certain HCV gap areas. The network could be configured to ensure that 64 species achieve their conservation targets by adding certain gap areas. Including the habitats of the other 11 species provides different degrees of protection, and efficiency is improved. Conservation strategies for a given ecosystem typically are derived by considering the needs of the human inhabitants against three different priorities. Using C-Plan software to analyze the conservation management of the BKPF in the Changbai Mountain region could guide decision making for optimizing the conservation network in this most precious of mountainous ecological zones.