A compact zoom lens with 2.4X optical zoom is presented. Its effective focal length ranges from 3 to 7.2 mm and its angle of field ranges from 62° to 30°. The zoom lens belongs to three-groups structure, including the first fixed group and the second and the third variable groups, and consists of four pieces of lenses. The zoom lens configuration is negative-positive-positive(NPP) type. The first lens group is a single negative lens. The second lens group consisting of two lens elements is a positive lens group. And, the third lens group is a single positive lens. The second lens group can effectively correct chromatic aberration. All lens elements are made up of plastic materials. Modulation transfer function(MTF) is used to evaluate the zoom lens image quality. The MTF of zoom lens is greater than 0.3 at 142 lp/mm in the 0.7 field of view. The total track length of the lens is about 10.7 mm. Due to its excellent image quality, the lens can be applied to many consumer electronic products.