Wetlands are important contributors to the global carbon (C) cycle because they store large quantities of C in their vegetation and soil and exchange CO₂ actively with the atmosphere through photosynthesis and respiration.Plant biomass is a critical part of the primary production in wetland ecosystem that maintains the wetland health and quality.It also provides many ecosystem functions,such as C sequestration in alpine wetland.Therefore,biomass is the main link that relates aboveground and belowground ecosystem processes.We used the peatlands and swamp medows areas in the Gahai wetland of south Gansu province to investigate changes to plant biomass during degradation succession in an alpine wetland.The time-space distribution pattern of the area at different stages of wetland degradation was analyzed using the sample-plot survey method.Significance testing was conducted using one-way variance analysis (One-way ANOVA) and the Schaffer method.The results showed that 1) the aboveground biomass decreased gradually in the peatlands and swamp medows as degradation succession progressed.The reduction in aboveground biomass followed the order non-degraded peatlands (PI)(334.19 g/m²)> degraded peatlands (PⅡ)(290.72 g/m²),and was non-degraded swamp meadows (SI)(378.40 g/m²)>lightly degraded swamp meadows (SⅡ)(308.07 g/m²)> moderately degraded swamp meadows (SⅢ)(261.21 g/m²).The curves for the aboveground biomass seasonal dynamics for the two sites were seasonal dynamics of aboveground biomass was single apex types,the variation trends were the same,and they reached a peak value in August.The changes in the absolute growth rate and relative growth rate of aboveground biomass at each degradation stage on the same wetland types were consistent for each degradation stage on the same wetland types over the years the survey took places,but the values were different between years.The values for absolute growth rate and relative growth also varied depending on the degradation stage in the same wetland type.2) The belowground biomass decreased significantly in the two wetland types as degradation succession (P<0.05).The belowground biomass in PI was 23081.46 g/m² and was 12607.72 g/m² for PⅡ in the peatlands,and followed the order SI (4583.16 g/m²)> SⅡ (3008.63 g/m²)> SⅡ (1290.73 g/m²) in the swamp meadow.The seasonal variations in belowground biomass for each wetland type were different,but the earlier the growing season began and ended,the greater was the amount of belowground biomass.Belowground biomass decreased significantly (P<0.05) with soil depth and had a "T" shape distribution.The peat and swamp meadow belowground plant biomass was greatest in the 0-10 cm soil layer,and occupied more than 50% and 70% of their total belowground biomasses,respectively.3) The average root-shoot ratio for non-degraded wetland was higher than for degraded wetland between May and September.The root-shoot ratio seasonal dynamics showed that the earlier the growing season began and ended,the greater was the ratio,and the shorter the period of vigorous growth.These results provide a scientific basis for wetland planning and management and an accurate estimation of C balances in alpine wetland ecosystems.