Abstract: Based on field investigation and laboratory analysis, biomass characteristic of an ephemeral plant Alyssum desertorum in 3 habitats was compared.The results indicated that height, modules biomass and total biomass of plant within each habitat were significantly different, and coefficients of variation of lots of component were more than 70%.Biomass of root and stem increased in a power function with increasing of total biomass, and showed a similar power allometry growth pattern, and the fastest growth rate was showed on the stem biomass (b=1.153 4) in nature reserve plot.Meanwhile, there was a positive power function or a linear relationship between leaf and fruit biomass with total biomass, the similar pattern was observed in the relationship between fruit biomass and root biomass, stem biomass and leaf biomass.For A.desertorum populations, biomass component and growth situation can be similar or different both within and between habitat, which is controlled by the interaction between environmental and genetic factors.