Abstract: The geotechnical properties of undisturbed Xinyang clay sampled from main campus of Xinyang normal university are experimentally investigated.The results are drawn as follows: (1) The silt content is 57.0%, the clay content is 42.4%, the liquid limit is 41.6%, and the plastic limit is 18.8%, so the soil is the lean clay (CL).The liquidity index is 0.19, so the soil is hard.The optimum water content is 14.7%, while the maximum dry density is 1.88 g/cm³.(2) The cation exchange capacity (CEC) is 206 mmol/kg, and the free swelling ratio is 40%, so the swelling potential is weak.(3) Nonclay minerals including quartz, plagioclase, and ankerite account for 69.7%.Clay minerals including kaolinite, illite, chlorite and illite/montmorillonite mixed layer account for 30.3%.(4) The preconsolidation pressure is 454.1 kPa, and the overconsolidation ratio is 7.7, so the soil is heavily overconsolidated.The compression index is 0.283, the swell (expansion) index is 0.038.(5) The effective cohesion of peak shear strength is 33.6 kPa.The effective friction angles of peak and residual shear strength are 25.5° and 23.7°, respectively.(6) The coefficient of permeability is 5.97×10^-7 cm/s which measured by the falling-head permeability test.