Abstract: A new photocatalytic system for producing hydrogen using zinc tetracarboxylph-thalocyanine as sensitizer has been investigated. It was found that the presence of ca-tionic surface active agent in aqueous solution was in favor of the reduction of concentration of zinc tetracarboxylphthalocyanine dimers which was the inactive species in the photo reaction. It could also improve the charge seperation so as to increase the efficiency of photocatalytic reaction in the four-component system. The mechanism of evolution of hydrogen in the four-component system has been briefly discussed.