The alignment characteristics and dynamics of SiO2 particles dispersed in a liquid crystal (LC) under an applied electric field have been studied. In the system composed of LC, surfactant and SiO2 particles, a well-ordered aggregation of particles has been observed under the applied electric field. For this aligned aggregation of particles, phase separation behavior between the LC and surfactant, and electrohydrodynamic flow at the LC/surfactant interface seem to play an important role. The possibility for the fabrication method of photonic crystal is also discussed.