Evaporation self-assembly method, which is used to assemble sub-micrometer polys tyrene microspheres, is presented in this paper. In this process the polystyrene microspheres are effectively assembled at the gas-liquid interface of suspensio n as moisture evaporates at fixed temperature. The scanning electron microscope shows that the three-dimensional colloidal assemblies have regular close-packed face-centered cubic structure. It was shown that the evaporation was blocked by the polystyrene colloid crystals growing at the gas-liquid interface, and the am ount of the polystyrene microspheres transferred to the colloid crystals from th e suspension in unit time increased with the area of the assemblies. High-qualit y polystyrene colloid crystals can be assembled when not changing or decreasing the phase concentration, whose changes can be controlled by adjusting the assemb ly area and the evaporation temperature.