A LED head sink module includes a LED module, which comprises a circuit substrate, a LED chip installed in the circuit substrate, a packing cup molded on the circuit substrate around the LED chip and a lens molded on the packing cup over the LED chip, a heat sink, which has a base and a flat mounting block located on the bottom side of the base for stopping against the circuit substrate of the LED module for absorbing waste heat, a bracket, which has a center opening that receives the circuit substrate of the LED module, first retaining members for fastening to a retaining portion at the periphery of the packing cup and second retaining members for fastening to the flat mounting block of the heat sink, and a water seal sandwiched between the LED module and the bracket to seal off outside moisture and dust.