The effect of underground deep mixed columns on mitigation of liquefaction was studied by running shaking table model experiments. The effects of several factors like frequency of input motion, the degree of drainage, column length, diameter, column spacing and boundary condition were studied. Moreover, the volumetric strain, the pore water pressure ratio, the rates of generation and dissipation of the PWP ratio, as well as the acceleration and deformation response of the soil were examined as indicators of the mitigation effects of the columns. It was observed that the use of underground columns can decrease the extent of liquefaction considerably from the viewpoint of all the aforementioned aspects of the liquefaction.