The invention provides an internal and external eccentric block combined type vibration exciter comprising a synchronous shaft and two bearing pedestals symmetrically arranged. A rolling bearing is assembled in each bearing pedestal. The synchronous shaft is installed on the bearing pedestals through the rolling bearings in a rotatable manner. The two ends of the synchronous shaft penetrate through the two bearing pedestals correspondingly. Multiple internal eccentric blocks and external eccentric blocks are sequentially installed on the synchronous shaft from the center position to the two ends. A protection barrel is installed between the two bearing pedestals and is arranged outside the synchronous shaft in a sleeving manner. The internal eccentric blocks are arranged in the protectionbarrel between the bearing pedestals. The external eccentric blocks are arranged outside the protection barrel. A belt wheel is installed at one end of the synchronous shaft. Existing eccentric shaftsare replaced with the two internal eccentric blocks, the weight of the whole machine is decreased, valid vibration excitation force is increased, and the machining efficiency and precision of the shaft can be improved. The internal eccentric blocks and the external eccentric blocks have a balance effect, the bending force stress borne by a connecting shaft can be reduced, and synchronicity of thevibration excitation force on the two sides is ensured.