The invention provides a variable focus liquid lens using electrowetting, comprising a conductive first liquid and an insulating second liquid. At least one of the first liquid composed of electrolyte and the second liquid composed of insulating liquid contains a surfactant for reducing interfacial energy between the first and second liquids. An interfacial portion between the first and second liquids is gathered by surfactant to reduce driving voltage. The variable focus liquid lens according to the invention has about 50% lower driving voltage required for changing focus, ensuring stability of the two fluids.