Abstract: In order to improve planting benefit of the dry-land soybean, and make full use of local rainfall resources, this experiment was conducted to find out the effects of planting density on grain yield and water use efficiency of dry-land soybean in dry-land of the eastern of Gansu. The results indicated that, as the planting density increased, the main economic characters that were the number of pods, seeds number per plant, number of seeds per pod and seeds weight per plant of every experimental variety decreased. There was no significant difference in field water consumption of the different types of varieties across the different planting densities. In the range of 90-270 thousand plants per hm² of planting density, suitable planting density of late-maturity variety, such as ‘Fendou 78’ and ‘Jindou 23’ were 180 thousand plants per hm² , suitable planting density of mid- maturity variety such as ‘Zhonghuang 30’ and ‘Jindou 19’ were 225 thousand plants per hm². This means that suitable planting density could improve seeds yield and water use efficiency (WUE) significantly.