This study was conducted to investigate the effect of thinning intensities on soil carbon (C) storage in Pinus densiflora stands, Gangwon Province, Korea. We measured soil C storage (0-30cm depth) and soil characteristics in the Pinus densiflora stands: 55-year-old stand and 25-year-old stand. Study stands were thinned in 2008 with different thinning intensities by stand density (control, Ct: 0%, moderate, M: 30%, heavy, H: 40%). Soil C storage was significantly different between thinned and unthinned plots only for the 55-year-old stand (69.6 for H, 62.1 for M > 57.0 for Ct), however, those in the 25-year-old stand were not different among plots (46.9 for Ct, 45.3 for H and 40.4 for M, respectively). These results suggested that the thinning can be applied for the forest management practices to increase C storage in forest soil, and plays an important role to influence C storage for the Pinus densiflora forests.