Dielectric barrier discharge (DBD) is a typical non-equilibrium high-pressure ac gas discharge. Recently, two types of DBD arrangements are developed; volume discharge (VD) and surface discharge (SD). Such devices are beneficial for industrial acceptance, since vacuum systems can be got rid of and devices operated in atmospheric pressure region. DBD is an excellent source of ideal energetic electrons with 1-10 eV and high density. Its unique advantageous is to generate low excited atomic and molecular species, free radicals and excimers with several electron volt energy. In this paper, the properties of microdischarge in DBD are discussed with their simulation. Due to its attractive characteristics, DBD is recently widely studied for potential industrial applications. Ozone generators, excimer radiation sources, free radical generation and their applications in pollution control and monitor are also discussed.