Forest plays a vital role in water and soil conservation, wind prevention and sand fixation. The Yellow River Basin, as an important ecological barrier and economic belt in China, has received growing public attention. However, the lack of research on forest ecological security in a specific area is the main difference between related domestic and foreign studies. Therefore, this study takes 69 districts in 9 provinces of the Yellow River Basin as the research object, and uses entropy weight method and spatial correlation analysis to calculate the forest ecological security index and analyze its spatio-temporal evolution patterm. We draw the following conclusions. (1) For the forest carrying capacity indicators, the proportion of natural forest is the largest and its corresponding weight is 0.0800. For the social and economic pressure indicators, government forestry investment accounts for the largest proportion with a weight of 0.1189. (2) The forest ecological security index of the nine provinces is on the rise. The order of the forest ecological security index of the nine provinces is Ningxia > Shaanxi > Shanxi > Sichuan > Gansu > Inner Mongolia > Shandong > Henan > Qinghai. From an overall perspective, the forest ecological security index on the south bank is higher than that on the north bank of the Yellow River Basin, while the forest ecological security index in the central and eastern Yellow River Basin is higher than that in the western regions. (3) The forest ecological security index of the Yellow River Basin shows significant clustering characteristics. The high-high agglomeration areas of forest ecological security index are mainly distributed in the central and southern regions, and the low-low concentration areas are mainly distributed in the western Qinghai Province. Based on the above analysis, the following countermeasures and suggestions are put forward:(1) According to the spatial distribution characteristics:① the south bank of the Yellow River Basin needs to pay special attention to forest fire prevention, forest disease and pest control and management, etc., while the forest product trade and forest tourism can be appropriately developed. ② the north bank of the Yellow River should promote afforestation and forestry engineering construction, strengthen forest cultivation and management, and prevent soil erosion. ③ While actively implementing projects such as returning farmland to forests, the Yellow River Basin areas must also strengthen the construction of nature reserves to maintain the results of returning farmland to forests. (2) For spatial correlation analysis:① High-high agglomeration districts and counties should develop under-forest economy without destroying forest resources. ② Districts and counties in low-low agglomeration areas should focus on ecological restoration and forest resource protection, speed up plantation construction and pest control, strengthen forestry protection projects, establish ecological protection zones, and take other related measures to ensure regional forest ecological security. ③ Districts and counties in high-low agglomeration areas and low-high agglomeration areas should strengthen the radiation function of high-value areas. Sustainable economic and ecological development can be achieved by vigorously developing the proportion of industries with high clean production level and reducing the proportion of "high energy consumption and high pollution" industries. In Addition, the Yellow River Basion should promote and build a more efficient market environment for the flow and application of production factors throughout the basin, and realize the win-win of economic development and ecological protection.