An integrated optical system design method for LED automobile headlamp is prsent，and an asymmetric dual freeform surface lens is designed for low and high beam. The illumination width of near light can reach 16 meters by using variable focal length ellipsoid reflector and asymmetric double free surface lens. The simulation results show that the illumination value and light type required by the high and low light points of the headlamp meet the national standard， and the color temperature of the spot is stable. The volume of the designed optical system is half of that of the traditional headlamp， which conforms to the requirements of the compact headlamp design.