In the present work, CoS2 and CoS2-CNT were irradiated by visible light respectively. The generation of reactive oxygen species were detected through the oxidation reaction from 1,5-diphenyl carbazide (DPCI) to 1,5-diphenyl carbazone (DPCO). The composite obtained was also characterized by transmission electron microscopy (TEM), Raman and UV-vis analysis. From the photocatalytic results, the excellent activity of the CoS2-CNT composites for degradation of methylene blue under visible irradiation could be attributed to both the effects of charge transfer to carbon nanomaterial, and the introduced CoS2 to enhance the photogenerated electrons transfer. (C) 2013 Elsevier B.V. All rights reserved.