To improve our understanding of responses of soil temperature to global warming in forests, we conducted a soil warming experiment in a subtropical evergreen broadleaved forest in Ailao Mountains, Yunnan, SW China. Based on measurements from 2011 to 2013, we examined warming effects on seasonal and diurnal patterns of soil temperature. The results showed that warming effects in dry season were greater than in rainy season, showing seasonal variations, but not diurnal variations. Soilsurface temperatures increased between January and April, with a 3 ℃ maximum in February. Warming increased soil temperature by 2 ℃ at the soil depth of 5 cm. The warming effect decreased exponentially with soil depth. Based on a 0.5 ℃ temperature increase, soil warming could reach the depth of 3.82 m in the dry season, 12.04 m in the rainy season, with an annual mean of 6.58 m.