A series of jungle-like bismuth oxide/bismuthyl subcarbonate (Bi₂O₃/Bi₂O₂CO₃; denoted as BO/BOC) heterojunctions containing tunable dosage of oxygen vacancy (denoted as OV) and phase composition were prepared with β-Bi₂O₃ possessing a large amount of OVs (denoted as OVs-BO) as the precursor in the presence of carbon dioxide and water vapor. During the in-situ growth of OVs-BO/BOC heterojunctions, BO and BOC intimately contact at the interface to yield the jungle-like OVs-BO/BOC catalysts with an increased specific surface area. In the meantime, the OV concentration and phase composition of the as-fabricated OVs-BO/BOC catalysts can be regulated by adjusting the reaction time. The photocatalytic activity of as-prepared OVs-BO/BOC catalysts for the degradation of methylene blue (MB) and tetracycline hydrochloride (TC) under visible-light irradiation was evaluated. Results show that OVs-BO/BOC heterojunctions exhibit higher photocatalytic activity than OVs-BO and OVs-BOC; and OVs-BO/BOC-0.75 h (obtained at a reaction time of 0.75 h) contains about 47.5% (mass fraction) of β-Bi₂O₃ has the highest photocatalytic activity. This is because the oxygen vacancies in OVs-BO/BOC heterojunctions exhibit high visible light absorbance ability and the interfacial Z-scheme structure of OVs-BO/OVs-BOC contributes to efficiently separate and transfer electron–hole pairs.