The invention discloses a dynamic-balance ultra-precision turning machine tool capable of turning off-axis optical curved surfaces. The machine tool comprises an electric main shaft system, a transverse transmission system, a longitudinal transmission system and a matched tool body supporting table. The electric main shaft system is fixed to the machine tool body supporting table, the transverse transmission system is vertically installed above the longitudinal transmission system, and the longitudinal transmission system is vertical to the electric main shaft system. The electric main shaft system comprises a rotary actuation mechanism, a transverse auxiliary motion system and a main shaft box; the transverse transmission system comprises a knife rest system, a crank shifting fork mechanism, a gear transmission mechanism and a feeding box, wherein the knife rest system is placed on one side of the crank shifting fork mechanism in parallel, the gear transmission mechanism is placed below the knife rest system in parallel, and the feeding box is placed on the outside of the knife rest system, the outside of the crank shifting fork mechanism and the outside of the gear transmission mechanism. According to the machine tool, the machine tool can keep a dynamic-balance state in the machining process, machining precision is improved, the multiple off-axis curved surfaces can be turned, and machining efficiency is improved.