Photocatalytic degradation of reactive green using zinc oxide have been included in this work, which is achieved by the irradiation of suspended solution consists of different concentration of reactive blue with 0.12gm/100cm3 of mixed metal oxide semiconductor zinc oxide by using solar light. In order to study the effect of metal oxide zinc oxide in photocatalytic degradation of reactive blue, several experiments were acheived. Such as the effect of dye concentration, the effect of mass loading and effect of solution temperature.