Optical zoom system based on liquid lens is used in many optical fields in recent years because it can achieve zooming without mechanical movement. A new lens with three layers of liquids and connected conducting layer is proposed. This liquid lens is cylindrical and it can zoom and compensate by itself by changing the voltages applied to control the radium of liquid interfaces. The structure of the liquid lens is analyzed in detail, and the minimum structure expression of the liquid lens is obtained. On the basis of the Gaussian optics theory, the effects of lens parameters on zooming performance including zoom ratio and field angle of the system are studied.