The study was conducted in May, July and September 2020 in the grazing exclusion plots (5 a) and grazing plots of the experimental area in the middle part of the northern slope of Tianshan Mountains. The quantitative characteristics (height, cover, density and biomass) and component (stem, leaf and root) biomass of Seriphidium transiliense in the grazing exclusion plots and grazing plots in different months were measured and analyzed to reveal the characteristics of plant populations and component biomass in response to the grazing exclusion, and to provide a basis for the restoration and rational use of degraded grassland. The results showed that: (1) compared with the grazing plots, the height, coverage and biomass of S. transiliense in the grazing exclusion plots increased significantly (P<0.05) in May, July and September, with the increase in height ranging from 69.90% to 95.53%, the coverage ranging from 186.53% to 297.82% and biomass ranging from 86.24% to 631.83%, respectively. (2) As the months progressed, the single plant biomass, stem biomass and leaf biomass of S. transiliense showed decreasing and then increasing trend in both the grazing exclusion plots and grazing plots, while root biomass showed an increasing trend. The grazing exclusion changed the proportion of plant components, with the proportion of stem and leaf biomass to plant biomass increasing significantly in July and September, while the proportion of root biomass decreased significantly in the grazing exclusion plots compared to the grazing plots. The study concluded that grazing exclusion facilitates the recovery of above-ground vegetation, which changes its building block structure, and is an effective measure to restore vegetation in degraded desert grasslands.