The orthogonal design t est was used to quantitatively analyze the influencing factors and influence degree of compressive strength，shear strength index，and permeability coefficient of improved loess，and the optimal content of improved loess was obtained.In addition，the improvement mechanism of nano-clay materials on loess was explored by scanning electron microscopy.The results show that：① The factors affecting the compressive strength of improved loess are the content of nano-clay，water content，and curing age，and the factors affecting cohesion，internal friction angle，and permeability coefficient are the content，dry density，and confining pressure.② Under different influencing factors，nano-montmorillonite can effectively improve the compressive strength of loess than attapulgite.③ When the material content is less than or equal to 1%，the shear strength index of improved loess by attapulgite is generally higher than that by nano-montmorillonite，and the permeability coefficient is opposite.However，when the material content is greater than or equal to 2%，the situation is different.④ When the attapulgite content is 1%，and the nano-montmorillonite content is 2%，the surface of the improved loess is the densest，and the porosity is the smallest.