Soil seed bank is the renewal source of standing vegetation and researches on it become quite active in the area of plant population ecology.This paper studies the species composition,density,diversity,and the relationship between seed and standing vegetation about soil seed bank of Melilotoides ruthenicus var.in 2 schanicus community on the arid grassland in the upstream area of Shiyang River. Results showed that a total of 20 plant species belonging to 12 families were found in the soil seed bank. The density and specie of soil seed bank increased with the decrease in Melilotoides ruthenicus var. inschanicus’s coverage in the horizontal distribution. The vertical distribution of density changed in the order of 0-5cm>10-15cm>5-10cm soil depth,but the species decreased with the increased depth. There was no seed exist in the grassland com 2 munity where the Melilotoides ruthenicus var. inschanicus’s coverage is more than 60 %. With the decrease in Melilotoides ruthenicus var. inschanicus’s coverage,the Margalef richness index,Shannon-Wiener diversity index,and Pielow evenness index of the soil seed bank showed a rising trend,but ecological dominance showed a descending trend,decreasing from 0.46 to 0.24. The similarity coefficient of the soil seed bank and standing vegetation varied from 0.29 to 0.58.