Abstract: Aiming to measure and analyze the internal coordination of sustainable development in forestry sector of Heilongjiang Province, this study first categorizes the sustainable development of Heilongjiang's forestry into economic, social, and ecological subsystems. The time frame spans from 2015 to 2019, during which the index systems for each subsystem are constructed and data is collected. The comprehensive index of sustainable development in Heilongjiang's forestry, as well as the subsystems of forestry economy, society, and ecology, are calculated using the full permutation polygon comprehensive diagram method. Subsequently, the distance coordination degree model is applied to quantitatively analyze the coordinated development relationships among the subsystems of forestry economy, society, and ecology within the sustainable development of Heilongjiang's forestry. The results indicate that the overall level and grade of sustainable development capacity in Heilongjiang's forestry have been steadily improving year by year from 2015 to 2019. Among them, the ecological subsystem of forestry has a significant growth contribution rate and a high growth rate. There are changes in the contribution differences of individual indicators within the forestry economic and social subsystems. Additionally, the coordination degree between forestry economic and social benefits is at a relatively high level, with consistency in development level and speed. The comprehensive development degree and coordination degree of forestry economy and ecological benefits have shown an increasing trend over the years. However, there is a weakening trend in the coordinated development effect between the social subsystem and the other two subsystems. Overall, the internal coordination development level of Heilongjiang's forestry sustainable development from 2015 to 2019 is still in its initial stage. It is significant to continuously promote a higher degree of integrated development among the various subsystems of forestry sustainable development.