The invention discloses an internal excitation automatic balance device for a propeller. The internal excitation automatic balance device is installed at a propeller shaft, and imbalanced vibration ofthe propeller can be inhibited online. The internal excitation automatic balance device is of a cyclic structure, and mainly comprises a static ring and a movable ring. The static ring comprises a magnet excitation coil and a balance weight disc positioning Hall sensor; the movable ring comprises two balance weight discs into which permanent magnets and balance weight blocks are embedded, and when there is no external magnetic field, position self-locking is achieved through side magnetic plates; the static ring is connected with the movable ring through a bearing. When the coil is powered on, the balance weight discs can generate stepping rotation, and imbalanced compensation is conducted. By means of the device, the mounting structure can be designed according to the actual demand of the propeller, and is suitable for different mounting modes an different balance capability requirements separately. The device has the advantages in the aspects of the weight of the magnetic excitationcoil, the balance capability, the mounting convenience and the like.