Because the security of the forest ecosystem is related to human survival and development, this paper took 1,107 districts and counties in the Yangtze River Economic Belt as research objects. The entropy weight method, ArcGIS and GeoDA software, the center of gravity analysis model and spatial correlation analysis were used to analyze the Forest Ecological Security Index (ESI). The following conclusions were drawn. (1) In the forest status index, the highest weighted indicator is the forest fire disaster rate, followed by the forest pest damage rate and forest land area ratio. In the forest pressure index, the indicator with the highest weight is the intensity of government forestry input, followed by the annual afforestation ratio and the proportion of nature reserves. (2) From the perspective of the whole region, the forest ESI values are ranked as the upper reaches of the Yangtze River > the middle reaches > the lower reaches. The forest ESI value in the south bank of the Yangtze River is higher than that in the north bank. The overall level of forest ESI in the Yangtze River Economic Belt is relatively low, but it generally showed an upward trend from 2000 to 2015. From the perspective of each province, Yunnan Province has the highest forest ESI value (19.77%), while Shanghai has the lowest one. In the 15-year period, the forest ESI value in Hunan Province has increased the most, and Jiangsu has the smallest increase (0.76%). (3) The forest ESI values in each tributary are in the order of Ganjiang > Yongjiang > Jinshajiang > Wujiang > Xiangjiang > Hanjiang > Jialing River > Yongjiang. From 2000 to 2015, the forest ESI values of the eight major river basins generally showed an upward trend, among which the Xiangjiang River Basin had the largest increase (20.87%) while the Jinsha River Basin had the smallest increase (3.6%). (4) The center of gravity of the forest ESI value has successively experienced the process from south to west, west to northeast, and northeast to south. (5) The forest ESI value of the Yangtze River Economic Belt has a relatively obvious agglomeration. The forest ESI values high-high concentration areas are mainly distributed in Sichuan and Yunnan Provinces, and the low-low agglomeration areas are mainly distributed in Shanghai, Jiangsu and Anhui, followed by Hubei Jianghan Plain and Sichuan Chengdu Plain. (6) Based on the above analysis, this paper suggests that i) attention should be paid to forest fires, pest control, forestry investment, and afforestation. ii) From the perspective of the whole region, the focus of ecological restoration should be on the lower reaches of the Yangtze River. From the perspective of tributaries, Minjiang, Jialing and Han rivers should focus on strengthening forest restoration. iii) It is necessary to strengthen the afforestation and conversion of farmland to forests in the low-low agglomeration areas such as Shanghai, Jiangsu and Anhui, and to appropriately develop wood processing and under-forest planting industries in the high-high agglomeration areas such as Sichuan, Yunnan, Jiangxi and Zhejiang.