A rotary engine that includes at least two sets of baffles that are arranged between a cylinder body and a rotor, and are in seal fit with the inner wall of the cylinder body to form at least two sealed cavities in the cylinder body; at least one set of the baffle is a movable baffle, and can rotate around the center of the cylinder body; a one-way rotation mechanism is arranged between the movable baffle and the rotor, and drives the rotor to rotate in one direction. The rotary engine has the benefits that the sealed cavities are formed by the movable baffle and the cylinder body; four working strokes including air suction, compression, ignition and exhaust are carried out in each sealed cavity; the movable baffle rotates under acting and counter-acting forces, drives the one-way rotation mechanism to rotate, and then drives the rotor to rotate.