Cellulose represents the major component of the abundant and inedible lignocellulosic biomass on earth. The valorization of cellulose into liquid biofuels and high value-added bio-based chemicals has drawn intensive attentions in recent years. However, because of the rigid structure of crystalline cellulose, the breakage of beta-1,4-glycosidic bonds, the first step of cellulosic biomass utilization is still a critical challenge under mild conditions. Herein, we report the cleavage of beta-1,4-glycosidic bonds of cellobiose on Ir/HY catalyst with high activity and high selectivity (> 99%) under visible light illumination at temperature not exceeding 100 degrees C. We found that the hydrolysis of cellobiose under mild condition is mainly owing to a cooperation effect between the Ir nano particles as the plasmonic photothermal source and acid catalysis of HY zeolite. This work provides a distinctive, sustainable pathway to efficiently convert cellulose to chemicals driven by solar energy under mild conditions.