Bismuth enrichment as a common issue at the surface of bismuth vanadate (BiVO4) has been frequently reported as a severe limitation to its water oxidation kinetics. To address this problem, this study reports a novel approach to eliminate the surface bismuth enrichment by forming BiVO4/BiOCl heterojunction via surface hydrochloric acid treatment. Benefiting from type II band alignment of the BiVO4/BiOCl heterojunction, the treated photo-anode delivers excellent PEC performance with a photocurrent density of 1.83 mA/cm(2 )at 1.23 V (vs. Ag/AgCl), compared to 1.27 mA/cm(2) of untreated BiVO4 photoanode. This improvement could be attributed to the effective charge separation in heterojunction interface as the charge separation efficiency of BiVO4 increased from 28% to 41% at 1.23 V (vs. Ag/AgCl) after formation of BiVO4/BiOCl heterojunction.