A new kind of modification photocatalyst has been synthesized by coating CoPc on the interface CuxS and CdS. The photocatalytic activity for hydrogen generation from H2S decomposition has been investigated in aqueous suspension. Interaction between CoPc molecule and semiconductor, as well as its influence on photocatalytic ability have also been studied. The results proved that CoPc coating could markedly enhance the photoactivity of the semiconductor for H2S decomposition with the reaction rate of 2-3 time higher. The unlinear photoactivity increase was observed at different CoPc coating concentration. Furthermore, the photoactivity was dependent on the preparation method of catalyst. CoPc dependence appears to be more pronounced if coating CoPc on CuxS surface first. Photoactivity is not proportional to the concentration of the substrate, in the lower concentration range, CoPc coating effect is more pronounced. It was shown that catalyst activity increased markedly if using CoPc DMF solution with 10-5 mol•L-1 Cu2+ion. The reason proposed is that the catalyst absorption has shifted to longer wavelength range with CuPc formed by exchanging of Cu2+ ion and Co2+ ion. The possible mechanism has been also discussed.