An internal fixation plate for sternoclavicular join comprises a locating rod junction and the clavicle fixation segment, both with flat cross sections. The locating rod junction and the clavicle fixation segment are not in the same plane, and the transition segment connects in between the locating rod junction and the clavicle fixation segment. The clavicle fixation segment is of a long strip, and screw holes are designed in the clavicle fixation segment. The locating rod junction is movably connected to the cylindrical sternum locating rod, through the connector, and allows the sternum locating rod to rotate and swing relative to the locating rod junction. The internal fixation plate connects the clavicle fixation segment to the sternum locating rod through a movable connection, so as to prevent the sternum locating rod from scratching and enlarging the bone holes in sternum.