A suspension of charged silica colloids was forced to flow in a flat capillary cell using an air-pulse-drive system. Above a critical air-pulse pressure, almost the entire capillary space was filled with a single-domain crystal with high spectral quality. The obtained flow-aligned particle arrays in water were immobilized as a self-standing hydrogel film using a photo-polymerization technique, thereby preserving the high quality. These results are basically the same as those for the previously reported polystyrene colloidal crystals, and they indicate that the present method is widely applicable to various kinds of particles.