The invention discloses a novel Y-Deltastarting box which comprises a breaker, fuses, a separating brake knob, a switching knob, a time relay, a motor protector, and three sets of alternating current contactors. The motor protector is an electronic motor composite protector, a coil of the electronic motor composite protector is connected with a coil of a contactor KA in parallel, and a normally-closed contact of the electronic motor composite protector is connected in series in a secondary protection circuit. An original thermal relay is replaced by the motor protector of JD 5serial with an integrated mode totally closed structure, and accordingly a three-phase alternating-current motor is protected. The novel Y-Deltastarting box integrates overload, phase lack, interior star triangle phase loss, stall and three-phase imbalance protection and fault and operating characteristic indication functions, and has a fine inverse-time characteristic. The novel Y-Deltastarting box is provided with functions of operating indication, phase loss fault indication and overload alarm, and is convenient to mount and debug, striking and direct, and is quick in fault removing.