The performance of photoelectrochemical (PEC) CO2 reduction on a photocathode is determined by the light absorption, charge separation and charge transfer efficiency of the photocathode according to eta(total) = eta(abs) * eta(sep) * eta(tran). Herein, we for the first time establish a photocathode for CO2 reduction on the base of commercially-available p-type Cu(In,Ga)Se-2 (CIGS). CIGS has a very high optical absorption coefficient up to 105 cm(-1) in wide wavelength region. It reaches an ultrahigh photocurrent density of 4.8 mA cm(-2) at -0.2 V vs. RHE and 11.5 mA cm(-2) at -0.7 V vs. RHE. Importantly, by fixing the bias at -0.2 V vs. RHE, the CIGS/CdS/ZnO/AZO photocathode selectively converts CO2 into CO with a faradaic efficiency of 99.3%. This is the highest record among the state-of-the-art photocathodes for CO2 to CO. Our work opens new opportunity for CIGS in solar-induced chemical reactions, and is expected to be concerned by researchers who are interested in catalysis and PECs. (C) 2020 Elsevier Inc. All rights reserved.