In the Da Xiang'anling Mountains, vegetation has relatively high albedo, surface coverage, and capability for water holding and retention, which have large impacts on the thermal regime in soils and permafrost hydrology. In order to understand the influences of different types of forests on frozen ground temperatures and the freeze-thaw processes, five respresentative forests, including a Ledum palustre var. dilatatum-Bryum-Larix dahurica forest , a Bryum-L. dahurica forest, Betula fruticosa L. dahurica forest , and a Carex tato-L. dahurica forest in the experimental area at the China Forest Ecological Research Network (CFERN) Station near Genhe in the Da Xing'anling Mountains, and a Carex tato swamp in the nearby Yitulihe, were chosen for monitoring ground temperatures in the active layer with depths from ground surface to 1.6 m and at shallow depths in permafrost. Ground surface temperatures vary considerably due to the combined influences of albedo, coverage and capability of water holding and retention in these five types of forest. In summer, the mean monthly ground surface temperatures decline in the order of the Bryum-L. dahurica forest, the Ledum palustre var. dilatatum-Bryum-L. dahurica forest , the Carex tato swamp, the Betula fruticosa L. dahurica forest, and the Carex tato- L. dahurica forest. Due to the shading effect of larch stands and shrubs, the mean monthly ground surface temperature of the Carex tato- L. dahurica forest is about 10 ℃ lower than that of the Carex tato swamp. In addition, ground temperature monitoring was carried out in the Betula fruticosa L. dahurica forest between two boreholes. At one of which the aboveground vegetation was reaped in July 2009. The vegetation at the other was undisturbed for comparison. The comparisons indicate that the vegetation clearance has a major impact on ground temperatures in the active layer (shallower than 0.8 m in depth) in August, September and October. In summary, vegetation in forest area mainly cools the soils in warm season, but it serves as an insulator in cold season. Moreover, the cooling effect in warm season more than offsets the insulation in cold season, resulting in an overall cooling effect in the active layer. Moreover, the Carex tato- L. dahurica forest with the highest water retention capability by plant roots system was the latest for ground freezing and thawing, simultaneously with the slowest ground surface cooling rate of 0.10 ℃/d and nearly 0 ℃/d below 0.2 m. Since its soils was covered mostly by herbaceous plants, usually withered more rapidly than the Bryum covered surfaces, ground surface cooled faster too in the Betula fruticosa L. dahurica forest, with the value of 0.96 ℃/d higher than that in the Ledum palustre var. dilatatum-Bryum-L. dahurica forest (0.75 ℃/d) and the Carex tato swamp (0.76 ℃/d), but soil at the depth of 0.5 m and 0.8 m froze slowly as a result of the high water retention capability by the roots of Carex tato. Due to poor-grown larch and shrubs, the cooling rate at the ground surface in the Bryum- L. dahurica forest reaches 1.22 ℃/d. And for lack of larch and shrubs in the Carex tato swamp, the underground cooling rate is higher than other forest types.