In this thesis, we study automobile low beam for ECE regulation based on white-light LEDs. First at all, we study the optical model of phosphor-based LED with scattering model of phosphor. Then, we design the headlamp for ECE low beam. In the design, a 15° wedge structure for special package is proposed. We also design the imaging lens, and based on it, we study the energy efficiency as well as the management of étendue. Finally, we simulate the light pattern by the headlamp and check the pattern with ECE regulation.