Abstract: Based on the soil water content data from the Flux Observation System of ChinaFlux installed in a subtropical evergreen broadleaved forest in the Ailao Mountains, Yunnan Province of Southwest China, the temporal variation and its affecting factors of soil water content in the forest were analyzed, aimed to further understand the characteristics and the annual variation pattern of the soil water content, and to provide basis to study the carbon sequestration ability, potential, and rate of local forest. In this forest, the soil water content at different depths more or less presented a single peak curve. With decreasing depth, the soil water content decreased, and its fluctuation range also had a gradual decrease, with the minima occurred in March and the maxima in July, August, and September. In the 0-100 cm profile, the soil water content in different layers ranged from 17.7% to 39.5%, with the minima and the least fluctuation at the depth 100 cm. Overall, the soil water content was higher in rainy season than in dry season. The soil water content was mainly affected by precipitation, soil temperature, and relative humidity (P<0.05). The maximum soil water content at the depth 5 cm in the subtropical evergreen broadleaved forest in Ailao Mountains was about 38%.