This paper proposes a zoom lens system based on liquid lenses. The system design consists of a fixed lens and four two-chamber liquid lenses. The chambers are filled with different liquids. The design principle is analyzed. Optimization method is used to get the optimal solution. With the solution, the proposed zoom lens system can obtain achromatic and spherical aberration corrected images in a particular zooming range, and no moving element is needed in the proposed zoom lens system. By choosing proper liquids, it can be designed to work within particular working regions with improved optical performance. We give the detailed simulation examples. The results indicate that the proposed design can help to improve the optical performances of zoom lens systems.