A novel Cu2O nano-whiskers with diameter of 6 ~ 12nm has been synthesized with the method of chemical deposition by adding surfactant cetyltrimethylammonium bromide (CTAB) as a template. The structure of the nano-whiskers has been characterized with XRD, SAED, TEM and XPS. The results show that the nano-whiskers exhibit a well crystallized 1D structure about 300 nm in length, and they are self-assembled by Cu2O quantum dots. Under visible light, the degradation efficiency of p-chloronitrobenzene with the Cu2O nano-whiskers as photocatalyst can reach 85.8%.