Compared with LED lamp, laser lamp has the advantages of small energy consumption, small volume and high brightness. It is a new direction of automobile lamp development. An optical system structure of low power and high brightness laser lamp is proposed. By building an optical test platform, the characteristic parameters of laser-driven white source are studied, which include the shape and size of the light spot and luminous flux. The light source model is established. The mapping relationship between the energy of point source and receiving surface is solved, and the initial surface shape of lens is solved. According to the source model studied, the initial lens is optimized, and the final design meets the requirements well. The designed aspheric lens is realized by ultra-precision machining, and the laser lamp is assembled and tested. The illumination at 25m is about 106lux driven by 12.16W electric power.