In order to evaluate the feasibility of improved clay based on sewage sludge ash(SSA) used as landfill liner-soil materials, a series of the direct shear strength tests and low temperature nitrogen adsorption tests were carried out to analyze shear strength and pore structure of improved clay in laboratory. The improved clay was composed of 95%-99% of raw clay and 1%-5% of SSA. The results show that the isotherms of improved clay containing SSA is belong to type VI isotherms, and it had type H3 hysteresis loop; The pore of improved clay was mainly composed of mesopore of 2-6 nm. The shear strength of raw clay corroded by landfill leachate sharply decreased. The cohesive strength and internal friction angle of sample declined 60.12% and 19.17%, respectively. The maximum adsorption capacity of raw clay corroded by landfill leachate declined 16.19%. The shear strength and pore volume of improved clay increased with an increasing of SSA.