The study used spatial distribution to replace time succession. We chose typical nondegraded meadow and degraded meadow plots in Maqin County, Guoluo Tibetan Autonomous Prefecture, Qinghai Province. Three 5 m×5 m quadrats were set up, plant and soil samples were taken in the morning from the end of June to September, and physiological indexes of Kobresia humilis, was measured to explore the effects of environment changes caused by degradation of Tibetan Plateau alpine meadow on physiological characteristics of K. humilis under natural conditions. The results showed that: (1) compared to nondegraded meadow, the available nitrogen content significantly reduced in degraded meadow (P<0.01), but the available phosphorus content and available potassium content significantly increased (P<0.05); The overall performance of total nitrogen, total phosphorus and total potassium contents were lower in nondegraded meadow than that in degraded meadow. (2) In degraded meadow, SOD activity of K. humilis leaves decreased in late growth stage (reduced by 4%), the trend of GSH content in two plots was basically the same. (3) The contents of soluble sugar and soluble protein in the leaves of K. humilis in degraded meadow were lower than that in nondegraded meadow at late growth stage (reduced by 17.6% and 34.9%, respectively), and significantly decreased in September (P<0.01). (4) After middle growth stage, the contents of chlorophyll a and b in the leaves of K. humilis of degraded meadow decreased more quickly than that of nondegraded meadow, and the contents were low (18.84% and 20.68%, respectively). (5) The generate velocity of O^-·₂ in the leaves of K. humilis in degraded meadow was higher than that in nondegraded meadow in September(P<0.01). These results indicate that K. humilis has higher ROS scavenging ability and osmotic adjustment ability. Environment change caused by degradation maybe the inner reason that resulted in K. humilis antioxidant capacity decrease and aging more earlier in late growth stage.