Abstract: To clarify the quantitative characteristics of carbon storage and carbon density of forest vegetation in Guangyuan City, and provide a basis for the development of forestry carbon sink, based on the comprehensive monitoring data of forest and grassland ecology in Guangyuan in 2023, this study estimated the carbon storage and carbon density of forest vegetation by using the biomass conversion factor method, aiming at revealing the carbon sink pattern and spatial distribution characteristics of the complex ecosystem in the hinterland of Qinba Mountain area. The results showed that: (1) The total carbon storage of forest vegetation in Guangyuan City was 4094.72×10² t, and the average carbon density was 36.26 t/hm², among which the tree forest contributed 97.02% of the total carbon storage, which was the core carrier of regional carbon sink function. (2) The carbon storage and carbon density showed obvious zonal characteristics in longitude and vertical direction. The high-value areas were mainly distributed in the mountainous regions around the Longmen Mountains in the northwest and the Qinling-Micang Mountains in the northeast, and the low-value areas were mainly located in the hilly areas in the south. (3) The carbon storage decreased with increasing altitude and was mainly concentrated in areas with an altitude of less than 2 000 m above sea level. The highest carbon storage was distributed in sloping areas with a gradient of 16° to 25°, and the carbon density on the shady slope/semi-shady slope was slightly higher than that of sunny slope/semi-sunny slope. Compared with historical data, the carbon storage of tree forests in Guangyuan City increased significantly in the past two decades, but the carbon density was still lower than the average level of national and Sichuan province, reflecting that there was still considerable space for improvement in forest quality. The results of this study could provide data support and decision-making basis for accurate assessment of forest carbon sink and regional ecological management in Guangyuan City.