A speaker box with side acoustic emission structure is disclosed. The speaker box has a cabinet having an acoustic window, a speaker unit mounted in the cabinet and including a diaphragm, a voice coil and a magnetic circuit, the diaphragm disposed in the side of the acoustic window and not faced to the acoustic window and having a dome and a suspension surrounding the dome, the dome having a plurality of reinforcements aligned in multi-row, the area of one of the plurality of reinforcements which is closest to the acoustic window that is maximum for improving vibration of the diaphragm.