In this paper we propose a projective LED low-beam headlamp of motorbikes. An ellipsoidal reflector is used to collect
light emitting from the LED source. A baffle plate is located in the focal point of the ellipsoidal reflector to form the
cut-off line.Then the light is redistributed by an optical lens. We set the measuring screen as an semi-circular zone and
divide it into many small lattices, divide the spatial angle of the LED source into many parts and make relationships
between them. According to the conservation of energy and Snell law, the lens is generated by freeform optics design
method. Then the optical system is simulated by Monte Carlo method using ASAP software. Light pattern of simulation
could meet the national standard. The low-beam headlamp is finally fabricated and assembled into a physical object.
Experiment results can fully comply with regulations GB5948-1998.