The solid interface of different slopes plays a significant role in influencing focus range and image quality of liquid controllable optical lens. In this paper, based on the theoretical model of liquid optical lens, the spherical aberration of the liquid optical lens is calculated. It is found that the spherical aberration is different from the two opposite sides of liquid optical lens, and at the same voltage range, the smaller the cone angle of the solid interface is, the larger the optical aperture of liquid optical lens changes. The spherical aberration of liquid lens can be minimized when a proper voltage is applied and a proper solid interface slope is selected.