Microwave-assisted direct photolysis (MADP) of bromophenol blue (BPB) in aqueous solutions was studied using microwave (MW) powered electrodeless discharge lamps (EDLs). BPB of initial concentration 100 mg/l was efficiently degraded in the MADP process after 10 min of irradiation by EDLs. The influence of factors as MW output power, light intensity and initial concentration of BPB on MADP degradation was investigated, respectively. Additionally, the identification of intermediates had been conducted by LC-MS and a possible reaction pathway for the degradation of BPB was proposed.