Abstract: The changing laws of heights of Deyeuxia angustifolia population in three vegetation types,ie.typical meadow,marsh meadow and swamp which are dominated by Deyeu xia angustifolia in sanjang plain are discussed in this paper.The results show that their increasements are all single peak type in the 3 vegetation types,their maximum values all appear at the end of July,respectively are 112.67cm,101.61cm,&83.88cm.The seasonal dynamics of HAGR are higher than 0,before the end of July,and then lower than 0,That maximum values of typical meadow and marsh meadow appear at the end of June to the middle of July,and that maximums appear at the middle to the end of June in swamp;the minimum value of typical meadow appears at the end of August to the middle of July,and,that of the other 2 types appear at the end of July to the middle of August.The seasonal dynamics of HRGR are the same as that of HAGR.The maximum value of marsh meadow appears at the end of June to the middle of July,and that of the other 2 types appear at the middle to the end of June.The minimum value of typical meadow appears at the end of August to the middle of September,that of the other 2 types appear at the middle of September to the beginning of October.

Key words: Height, Absolute increasing Rate, Relative increasing rate, Seasonal dynamics, Deyeuxia angustifolia population