A doubly excited fully superconducting synchronous machine belongs to the field of a motor and solves the shortcomings that a superconducting winding has large volume, high cost, and lower power density and large iron loss of the motor. In the invention, permanent magnets on an original axial-radial magnet flow fully superconducting synchronous machine are changed; the permanent magnets comprise 2p permanent magnets which are charged with magnetism in a tangential direction and 2p permanent magnets which are charged with magnetism in parallel or in a radial direction. The permanent magnets which are charged with magnetism in a tangential direction are rectangle panes and are embedded between an N-pole magnet conductive yoke and an S-pole magnet conductive yoke along the circumferential direction in a radiation way; and the permanent magnets which are charged with magnetism in parallel or in a radial direction are arranged on the N-pole magnet conductive yoke and the S-pole magnet conductive yoke. The charging magnetism directions of the permanent magnets of every two adjacent main magnetic poles are reverse. In the invention, the permanent magnet is applied to the superconducting synchronous machine to ensure that the permanent magnets generate idle load main magnetic flux and a superconducting field winding compensates demagnetization flux caused by armature reaction while the permanent magnets with low magnetic conductivity is arranged in a main magnetic circuit to suppress magnetic distortion of an air gap caused by the armature reaction.