Four soil samples of high-altitude permafrost from the Oinghai-Tibet Plateau were incubated in the laboratory for 90 days at 5 ℃, 15 ℃, 25 ℃ and 35 ℃ temperatures. The results showed that with increasing temperature, the soil respiration rate and cumulative amount of organic carbon decomposition presented a trend of increasing; during the incubation, the soil respiration rate reached a peak at first, then decreased continually, and tended to be steady after 15 days. At the same temperature, the soil respiration rate showed the following order： Tuotuohe （meadow marsh soil）〉Wuli （alpine meadow soil）〉Wudaoliang （alpine steppe soil）〉Ge＇errnu （grey-brown desert soil）, but the last three soil samples had no significant difference. Through the methods of density separation, acid hydrolysis, and chloroform fumigation, the soil organic carbon fractions were divided based on physical, chemical and biological views, respectively; meanwhile decomposition dynamic of organic carbon was simulated using the kinetic equations in two pools and three pools. It showed that dividing soil carbon fractions with different methods had significantly different results, and the proportion of active organic carbon accounting for total organic carbon was as follows., microbial biomass carbon 1. 26%- 10. 31%, light-fraction organic carbon 9. 13%- 20. 22%, easily oxidized organic carbon 28. 35%- 49.35%; that the results of model fitting through by dividing two or three pools were 0. 50%- 3.65% and 0. 51%- 3. 26%, respectively, and MRT were 8 - 56 d and 8 - 50 d, respectively, which were close; and that in addition, the proportion of active carbon from model approaches was significantly lower than that from experimental methods. Using linear, exponential and Gaussian models, the rule of change of soil respiration rate with temperature was analyzed. It was found that all of the three models can describe this relationship well, and Gaussian model was the best; the Q10 values from Gaussian model was also more agreed with that from incubation experiment. And Q10 decreased with increasing temperature, indicating that the response of the Qinghai-Tibet Plateau permafrost to climate warming will be more sensitive.%对采自青藏高原的4个高海拔冻土样品在5、15、25和35℃4个温度下进行了为期90d的实验室培养。结果发现，随着温度升高，土壤呼吸强度和有机碳累积分解量呈现出不断增大的趋势；在时间变化上，培养初期土壤呼吸强度达到最高值随后不断下降，15d左右以后达到稳定。同样的温度下，土壤呼吸强度呈现如下顺序：沱沱河（草甸沼泽土）〉乌丽（高山草甸土）〉五道梁（高山草原土）〉格尔木（灰棕漠土），但后3个土样之间差别并不显著。通过密度分选、酸水解和氯仿熏蒸方法，分别从物理、化学和生物学的角度对土壤有机碳组分进行划分，同时运用动力学方程分两库和三库对有机碳分解动态进行模拟。结果表明，应用不同实验方法划分的土壤碳组分差异明显，活性有机碳占总有机碳的比例从低到高依次是：微生物量碳占1．26％～10．31％，轻组有机碳占9．13％～20．22％，易氧化有机碳占28．35％～49．35％；分两库和三库拟合土壤不同碳库，二者的活性有机碳占总有机碳比例分别为0．50％～3．65％和0．51％～3．26％，MRT分别为8～56d和8～50d，结果比较接近；此外，应用模型方法所测活性碳比例显著低于实验方法的结果。采用线性、指数和高斯3种模型分析土壤呼吸速率随温度的变化规律，发现均能较好地描述二者关系且以高斯模型为最优，所计算出的Q10值也以高斯模型和培养实验较为契合；Q10值随温度的升高而减小，说明高寒气候条件下的青藏高原冻土对气候变暖的响应将比较敏感。
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