Based on measurements of soil bulk density and organic carbon content, this paper studied the characteristics of soil organic carbon density in degrading Achnatherum splendens communities around the Qinghai Lake. Results showed that soil bulk density under the heavily degraded Achnatherum splendens communities was apparently greater than that in the moderately degraded communities. Soil organic carbon content in the moderately degraded Achnatherum splendens communities was generally higher than that in the heavily degraded. Especially, there existed an extreme apparent difference in surface soil organic carbon content between them. In the 0-100 cm soil profile, soil organic carbon content showed a decreasing trend in the moderately degraded Achnatherum splendens communities and however, the heavily degraded communities displayed two kinds of trend, i.e., decreasing trend and the trend of first increasing and then decreasing with soil depth. Soil organic carbon density showed the same trend as its content. Soil organic carbon was mainly distributed in the 0-30 cm soil layer. Soil organic carbon densities in the layer in the moderately and heavily degraded Achnatherum splendens communities were 7.35 and 2.92 kg/m², respectively, occupying 57.45% and 63.06% of the total soil organic carbon densities in the whole soil profile. In the profiles, soil organic carbon densities in the moderately and heavily degraded Achnatherum splendens communities around the Qinghai Lake were 12.79 and 4.63 kg/m², respectively.