In this paper, powder spreading property in Wood-Plastic Composite(WPC) Selective Laser Sintering(SLS) rapid prototyping(RP) process is studied. WPC is more suitable for make parts by SLS according to its advantages, such as low-cost and green biological etc.. But as wood power is mainly composed of wood fiber and wood fibers have irregular shapes, easy to aggregate and block power spreading process, spreading powder uniformly on bed by leveling roller is difficult, resulting in bad shape quality of parts. In order to further improve powder spreading property of RP process, with optimal design of components, viscosity reducer calcium is added into WPC. Finally, as result of better powder spreading property, shape quality of the parts made by WPC is improved greatly and have good as well as with good laser sintering properties.