Manganese-based heterostructure catalysts display remarkable redox ability and considerable application potential in catalysis fields. The heterojunction (MnO/Mn₃O₄) catalysts with active interfaces and oxygen vacancies were successfully synthesized via a calcination method. Bisphenol A (BPA) was selected to evaluate the catalytic activities of synthesized heterojunctions. The degradation efficiency of MnO/Mn₃O₄-5 could reach 100% within 90 min, with a reaction rate (k value) calculated by pseudo-first order kinetics being 3-fold of MnO and 7-fold of Mn₃O₄, respectively. After calcination treatment, the presence of disordered interfaces, higher content of oxygen vacancies, and closer ratio of Mn(IV) to Mn(II) in the heterojunctions contributed to the enhanced catalytic performance. These features reduced the adsorption energy barrier of PMS molecules, facilitated the production of active species, thus promoted the redox reaction. This study illustrated a new view for constructing heterojunctions and provided an excellent catalyst for pollutants removal.