With three alpine meadow vegetation types of Tibetan Plateau (alpine meadow,alpine steppe and alpine desert steppe) as research objects,we made a fact-finding through the sample line method,quadrat method and nest quadrat method,respectively.Afterwards,we recorded all species of each transect line or per quadrat and mow the aboveground part of the quadrats.By the comparison of different alpine grassland plant diversity and aboveground biomass monitoring methods via the statistical analysis,we derived the minimum sampling area and the number of quadrats or transect lengths of different vegetation types of the Tibetan Plateau alpine grasslands.The results show that:in terms of species richness,400 m line transects observed the number of species accounts for 55%,71%,50% of all three methods’ investigation of alpine meadow,alpine steppe and alpine desert steppe,8 m² nest quadrats observed the number of species accounts for 57.5% and 57% of all the total number of species of the alpine meadow and alpine steppe separately,And 8 m² nest quadrats monitored the largest number of species of the alpine desert steppe,of which 2 m² number of observed species reached 83% in all possible species.The 20 sampling methods monitored largest number of species of the alpine meadow and alpine steppe,accounting for 78% and 86% of total number of species observed of three methods.Therefore,investigation of species richness is not less than 20 plots in alpine meadow and alpine steppe,alpine desert steppe required minimum area is not less than 2 m² of the two plots.Just in terms of aboveground biomass,the minimum number plots is not less than 7～11 derived from the relationship of coefficient of variation between aboveground biomass and the species,but by the coefficient of variation of aboveground biomass shows that the coefficient of variation is less than 5% of such premise.The sampling area of alpine meadow is not less than 0.25 m²;alpine steppe and alpine desert steppe is not less than 1 m².It can be drawn a conclusion that considering monitoring method of productivity,it will show great advantage for the alpine meadow to use 10 quadrates of 0.25 m²(0.5 m×0.5 m),but for the alpine typical steppe it will be better to choose 10 quadrates of 1 m²(1 m×1 m).However,for species richness of monitoring method,we obtain that it is convenient for the alpine meadow to chooses 20 quadrates of 0.25 m²(0.5 m×0.5 m) and for the alpine desert steppe the data should be accept 20 quadrates of 1 m²(1 m×1 m).Additionally,for alpine desert grassland it is prior to select 2 quadrates of 2 m².