Sandy pebble stratum is a kind of typical mechanical instability stratum. Shield tunneling often encountered difficulties such as unearthed difficulties， cutter disc wear and groundwater gushing. Aiming at the complex variability of the material composition and structure of this kind of stratum， sandy pebble soil sampling are selected in Luoyang Metro Line 2， and the properties of sandy pebble soil under different stone content are studied by using large direct shear test， slump test and permeability test. The results show that the shear strength and internal friction angle of sandy pebble soil increase nonlinearly with the increasing of stone content， and the shear strength and friction angle increase slow when stone content is less than 30%. The shear strength and internal friction angle increase significantly when the stone content is 30%~70%， and the shear strength and the internal friction angle are not obviously changed when the stone content is more than 70%. The slump of sandy pebble soil decreases with the increasing stone content and a demarcation rate of about 50% of the stone content is found. The permeability coefficient of sandy pebble soil increases with the increasing stone content and shows a similar rule like the shear strength and the internal friction angle.