In this work, a Bi 2 O 2.33 CdS direct Z-scheme heterojunction was fabricated based on energy band engineering. The Bi 2 O 2.33 core nanoflakes were first synthesized by electrodeposition which was followed by an annealing process to fabricate this heterojunction. Then the CdS shell was deposited on Bi 2 O 2.33 nanoflakes utilizing the solution method, during which a suitable concentration of CdCl 2 solution was used for forming a homogeneous and continuous integrated CdS shell. A space charge region and an internal electric field from CdS (+) to Bi 2 O 2.33 (−), which drove a direct Z-scheme charge transfer process, were formed at the interface. The Bi 2 O 2.33 CdS exhibited excellent photocatalytic performance for CO 2 reduction mainly attributed to the satisfactory photoinduced charge separation and transport efficiency in the direct Z-scheme heterojunction. The photocatalytic CO 2 reduction ability of Bi 2 O 2.33 CdS was significantly enhanced compared with single Bi 2 O 2.33 or CdS, with a CO yield rate of ca. 2.9 μmol/(cm 2 h) under a 300 W Xe lamp. The reduction of CO 2 to CO demonstrated 94.0% selectivity. Bi 2 O 2.33 CdS direct Z-scheme heterojunction with excellent photocatalytic performance for CO 2 reduction was fabricated based on energy band engineering.