The omni-directional reflection characteristics of one-dimensional photonic crystals composed of Ta2O5/MgF2 multi-quantum well (MQW) are studied using the transfer matrix method. An omni-directional reflector consisting of three and four Ta2O5/MgF2 MQWs is investigated. Results show that the photonic band gap of the photonic crystal composed of three and four Ta2O5/MgF2 MQWs, which are within the wavelength ranges of 402–712 and 412–1,023 nm, respectively, could cover the entire visible region.