This paper analyzes 4 types of group-pile which contains 4 piles with spacing 1.5D, 2D, 2.5D and 3D（D is diameter of the bearing plate）by numerical analysis, and draws some conclusions. The main conclusions are: group pile effect of DX pile increases sharply when pile spacing decreases；the bearing capacity of 3D spacing group-pile is 1.32 times larger than that of 1.5D spacing group-pile；effect coefficient of group-pile increases from 0.59 to 0.78 when spacing increases from 1.5D to 3D；the maximum value of settlement of soil among group-pile occurs between two bearing plates, and it decreases when the spacing of pile increases.