Soil is the largest carbon stock in the terrestrial ecosystem, storing about two-thirds of organic carbon in the terrestrial biosphere. Our understanding on the dynamic change of soil organic carbon belongs to one one of the important issue in terrestrial carbon cycle. Kobrecia humilis meadow is one major grassland type on the Qinghai-Tibetan Plateau, which has the high organic matter in soil. Under the dual effects of natural and human activities, there had great influence on the carbon balance alpine because the Kobrecia humilis meadows appeared different degree of degradation. To provide basic data and theoretical reference on accurate assessments of the Qinghai-Tibetan Plateau alpine meadow ecosystem carbon source/ sink effect, this paper determined the soil organic density through measuring the soil bulk density and organic carbon content under different degrading Kobresia humilis meadow in the Qinghai Lake basin. Our results showed that there existed discrepant in the soil organic carbon content and variable characteristics under different degrading Kobresia humilis meadow. The average organic carbon content in the 0100 cm soil profiles respectively was estimated at (25.174.73) g/ kg, (17.513.06) g/ kg,(20.791.30) g/ kg and (14.531.20) g/ kg from no degrading to heavy degraded Kobresia humilis meadow. That is, no degradation>moderate one >slight one >heavy one. Moreover, the mean of organic carbon content in 020 cm soil profiles from no degrading to heavy degraded reduced from (64.4711.70) g/ kg to (14.521.52) g/ kg, and fallen by 77.48%. Variations of the soil organic carbon density in the different degrading Kobresia humilis meadow soil profiles had the same trends of soil organic carbon content. From no degrading to heavy degraded Kobresia humilis meadow, the total organic carbon density in the 0100 cm soil profiles respectively amounted to (18.164.12) kg/ m~3, (14.24 3.52) kg/ m~3, (18.642.82) kg/ m~3, and (13.272.28) kg/ m~3, respectively. That is, moderate degradation> no one > slight one >heavy one. Soil organic carbon content mainly concentrated in the 040 cm depth. The 040 cm soil organic carbon density respectively was (32.066.41) kg/ m~3,(25.104.20) kg/ m~3, (2 2.683.17) kg/ m~3, (17.102.77) kg/ m~3, higher than 76.53%, 76.25%, 21.68% and 28.88% in 0100 cm soil total organic carbon density. If we do not think other factors, those results indicated that the degradation of the Kobresia humilis meadow caused that soil gradually released the organic carbon and weakened the store carbon function. Especially, surface soil was more prone to release CO_2 to the atmosphere due to the continuous climatic warming. Moreover, soil organic densities in Kobresia humilis meadow were evidently higher than the mean of alpine grassland and meadow in the Qinghai-Tibetan Plateau and in the Qinghai Province and across the China, highlighting that we could not neglect it in evaluation soil organic stock across the whole Qinghai-Tibet plateau.