Abstract: This study integrates multi-source data, including soil texture, soil type, and soil organic carbon (SOC) content, to analyze the spatial distribution characteristics of forest SOC stock in Yunnan Province and determine the SOC stock under different soil types.The results reveal that the total forest SOC stock in Yunnan Province generally exhibits a "high in the south, low in the north" spatial distribution pattern. Specifically, regions like Pu'er, Honghe, and Wenshan show higher forest SOC stocks (>170 Tg), whereas areas such as Zhaotong, Yuxi, and Dehong have lower stocks (<100 Tg). The SOC stocks in the remaining prefectures fall in between (100-170 Tg).The main forest soil types in Yunnan Province include low-activity strong acid soil, high-activity leached soil, initial soil, and high-activity strong acid soil (Note: These are common English translations of the Chinese soil type classifications). Among these types, high-activity leached soil has the highest SOC density (11.96 kg·m⁻²), while initial soil has the lowest (9.95 kg·m⁻²).A quantitative assessment of the impact of environmental factors on forest SOC stock found that mean annual evaporation is the most significant factor affecting SOC, followed by mean annual precipitation. As a crucial water input factor, annual precipitation directly influences soil moisture and vegetation growth, playing a vital role in soil organic carbon accumulation.