Abstract: Through the study on aboveground biomass and dynamic relationships among the components of Deyeuxia angustifolia population in typical meadow on Sanjiang Plain, the results showed that the seasonal dynamics of the aboveground biomass of population and that of its componentsstem, leaf and ear are all appeared the shape of single peak type, and reached their maximum values in July, which respectively were 996.95, 571.48, 441.58, 13.89g/m².the effect of linear regression was very good; they were appeared obvious linear relationships, the effect of parabolic regression was also good.F/C < 1 implied that its production efficiency was lower than that in typical grassland, but higher than that of Phragmites communis population in the same area and that of grass communty on Yellow Plateau in the north of Shannxi; the seasonal dynamics of F/C values and component ratio were relatively stable from the phase of before earing to the formation of hibernating bud, afterward F/C and leaf ratio abruptly fell down, this was accordance with the growth rhythm of Deyeuxia angustifolia population.

Key words: Deyeuxia angustifolia population, Aboveground biomass, Composition, F/C, Structure ratio