The invention belongs to the technical field of door closers, and particularly relates to a door closer based on a vane type swing oil cylinder. The door closer comprises the vane type swing oil cylinder, an output shaft and a torsional spring. The vane type swing oil cylinder comprises a stator provided with a stator vane, a rotor provided with a rotor vane, and two cover plates which are each provided with a plurality of screws. The rotor vane is provided with a through hole and a check valve. Through the damping function of the vane type swing oil cylinder and torsion of the torsional spring, when a door is pushed, thrust is converted into torsion of the torsional spring, when the door is closed, the door is opened and closed slowly, and impact and vibration of the door are prevented; the vane type swing oil cylinder is composed of the stator on the outer portion, the rotor on the inner portion, the upper cover plate and the lower cover plate and is good in leakproofness, simple instructure and easy to dismount and mount; and the check valve with a simple structure is mounted on the rotor, and the damping function of the vane type swing oil cylinder is achieved.