Abstract: [Objective] The purpose of this project is to study the variation of soil bulk density in the horizontal and vertical directions and the influence of the gravel content on the determination results of bulk density in the hope of promoting the standardization of soil analysis and soil resource management.[Method] Based on field soil survey,56 soil profiles were dug in grassland of the Ili Valley.Soils were sampled by using core method at uniformly set soil layers,and each layer was repeatedly sampled five times.Gravel content was measured in lab when it existed at a certain soil layer.The coefficient of variation (CV) was used to quantitatively express lateral variation of soil bulk density.[Result] The mean CV values of soil bulk densities measured from five samples for all soil layers were lower than 8;.Gravel could improve soil bulk density by about 16;.Soil bulk densities of varied soil layers at vertical direction were significantly different,and bulk density increased along with increasing soil depth.[Conclusion] Soil layer should be rationally classified when studying bulk density of soil profile in grassland.In view of the fact that highly stony soils existed in grassland of Xinjiang,we suggest that the relevant standard for measuring bulk density should be modified.