The performance and the characteristics of an oxygen acceptor prepared from barium peroxide and magnesium oxide were investigated for application to oxygen production. Reaction was run in an isothermal and isobaric condition, and the effects of temperature, oxygen pressure and the size of a sample pellet on the BaO-BaO2 equilibrium and reaction rate were investigated over a range of temperature 973-1173 K and oxygen pressure 0-0.3 MPa. It was found that both oxidation of barium oxide and reduction of barium peroxide are the first order reaction, and the BaO-BaO2 equilibrium and reaction rate vary markedly by the change of temperature and/or oxygen pressure but little affected by the size of a sample. Low temperature and high oxygen pressure are favorable to oxidation, and high temperature and low oxygen pressure are favorable to reduction. A reaction rate constant is independent of the starting BaO-BaO2 composition under fixed values of temperature and oxygen pressure. For a fixed equilibrium composition in oxidation or reduction, rate constants (k(o) + k(r)) at different temperatures are nearly the same. In the whole range of equilibrium composition, a rate constant k(o) increases with an increase in the mole fraction of barium peroxide at new equilibrium, while a rate constant k(r) increases with an increase in the mole fraction of barium oxide at new equilibrium.