(1) Background--With the blurring and disappearing of industrial boundaries, industrial integration has become an important direction of industrial development and transformation. The integrated development of agriculture and forestry has played an important role in promoting the transformation and economic development of the key state-owned forest areas. (2) Methods--The research data was collected from the "China Forestry and Grassland Statistical Yearbook" from 2011 to 2020 and the "Heilongjiang Statistical Yearbook" from 2012 to 2021. Based on the statistical data from 2011 to 2020, this paper used the industrial coupling model to measure the integration degree of agriculture and forestry in the key state-owned forest areas in Heilongjiang and analyzed the factors influencing the integration degree of agriculture and forestry by principal component analysis. (3) Results--First, the industrial scale of agriculture and forestry integration was the most important factor to promote the integration of agriculture and forestry in the key state-owned forest areas. Second, the technical level could promote the integration of agriculture and forestry in the key state-owned forest areas to a certain extent. Third, the effect of forestry industry structure on the integration of agriculture and forestry in the key state-owned forest areas was limited. (4) Conclusions and Discussions--According to the research results, the following conclusions are drawn: First, the industrial contribution of agriculture and forestry integration in the key state-owned forest areas in Heilongjiang showed an increasing trend year by year from 2011 to 2017, reaching a maximum of 26.001 in 2017, and a decreasing trend year by year from 2017 to 2019. The degree of agriculture and forestry integration in the key state-owned forest areas in Heilongjiang increased year by year from 2011 to 2018, reaching a maximum of 16.101% in 2018, and showing a downward trend year by year from 2019 to 2020. Second, the industrial scale of agriculture and forestry integration in the key state-owned forest areas in Heilongjiang had the greatest impact on the integration degree of agriculture and forestry. This was because the forest-related industries had a good foundation and positive externalities. The agglomeration effect produced by the development of these industries made the integrated development of agriculture and forestry in the key state-owned forest areas in Heilongjiang increasingly obvious. Third, the technical level of forestry workers played a certain role in deepening the integration of agriculture and forestry in the key state-owned forest areas in Heilongjiang Province. Forestry itself includes primary, secondary and tertiary industries. The key state-owned forest areas in Heilongjiang were ahead of agriculture in technological progress, and the degree of technological progress determined the level and scale of industrial development, and also determined the integration degree of agriculture and forestry. Fourth, the promotion effect of forestry industry structure on the integration of agriculture and forestry in the key state-owned forest areas in Heilongjiang was not obvious. The implementation of some national policies, such as the restoration plan of natural forests and the cessation of commercial logging of natural forests, had a great impact on the change of forestry in- dustry structure. It took a long time for these impacts to reflect the changes of industrial structure, thus affecting the promotion of agriculture and forestry integration. Based on the above research conclusions, the following policy recommendations are put forward: First, increase the proportion of agriculture and forestry integration industry in the key state-owned forest areas to promote the development of agriculture and forestry integration. Second, improve the vocational skill level of the forestry workers to promote regional economic development. Third, promote the integrated development of agriculture and forestry through top-level design. [ABSTRACT FROM AUTHOR]