A liquid crystal microlens driven by two voltages are reported. The two voltages cooperate to build up an axially symmetrical but spatially nonuniform electric field in a liquid crystal layer in the cell. One of the voltages remain unchanged biasing the reorientation of the liquid crystal directors outside the lens area, while the other one varies to adjust the gradient of the electric field in the lens area of the liquid crystal layer, and hence the properties of the lens. The focal length of the microlens increases monotonically with controlling voltage.