Soil organic carbon storage in grasslands reflects a balance between carbon inputs and the rate of its mineralization. The ability of different plant communities to capture, store and release carbon could lead to different carbon storage in grassland soil. In this study, the plant biomass and soil organic carbon (SOC) stocks of seven communities were investigated. SOC concentration differed significantly among the seven communities, varying from 4.08 g C kg(-1) for Suaeda glauca community to 9.18 g C kg(-1) for Echinochloa phyllopogon community. Over the entire profile to 100 cm, the SOC storage of E. phyllopogon community was highest with the value of 10.09 kg C m(-2), while the storage of S. glauca community was lowest with the value of 5.63 kg C m(-2). Over 30% of organic carbon was found in the top soils (0-20 cm). Compared to the Leymus chinensis community, halophytic communities have a great potential to store carbon in the Songnen grassland, with a mean value of 2.95 kg C m(-2) in the 0-100 cm soil layer. Vegetation has a great effect on the carbon storage of grassland.