The effect of different concentration of PVAc binder on the strength of clay was studied by unconfined compressive strength test and direct shear test. The test results show that: PVAc binder can improve the strength of clay;the unconfined compressive strength and shear strength of clay improved by PVAc binder increase with the increase of curing time;When the curing time is fixed, the cohesion and unconfined compressive strength of clay increase with the increase of PVAc binder content. While the concentration increases to 3%, the unconfined compressive strength of clay decreases compared with 2% concentration.