Abstract: A series of Cu2O/Ag(x) samples with different molar ratios were synthesized by a liquid phase reduction method. The properties of Cu2O/Ag(x) samples were characterized by SEM, XRD and DRS(UV-Vis-NIR) analyzing methods. The results indicated that in the presence of metallic Ag the light absorption of Cu2O/Ag(x) samples was greatly extended to visible and near infrared wavelength region. With increasing molar ratio of Ag the absorption intensities of samples enhanced. This implies that Cu2O/Ag(x) composite catalysts exhibit strong absorption of sunlight. The photocatalytic performances of Cu2O/Ag(x) composite catalysts in the darkness were evaluated using methyl orange (MO) as a degradation target. The results showed that Cu2O/Ag(0.05) sample exhibited the highest photocatalytic activity, while the degradation rate of MO (30 mg?L-1) reached 89.2% in 120 min. Meanwhile, the photocatalytic mechanism in Cu2O/Ag composite catalyst system was proposed.