The invention discloses a three-phase star AC motor and three-phase reactor dual-purpose winding. The three-phase star AC motor and three-phase reactor dual-purpose winding comprises a three-phase stator winding coil, an auxiliary switch circuit and two sets of three-phase external terminals. The winding is characterized in that, each-phase winding in a stator groove respectively comprises two parts of coils having identical turns, identical groove positions and identical winding modes, and each-phase winding is connected through the auxiliary switch. Through simple operation of the auxiliary switch, connection between the coils and between the coil and a terminal changes, the winding in one switch state is equivalent to a three-phase AC motor winding, in another switch state, the winding is equivalent to a three-phase reactor winding, so the dual-purpose effect is realized. In a certain type of a plug-in automobile and a grid connected distribution generator, an AC generator and a reactor are both necessary but not used simultaneously, through the dual-purpose effect, resource waste can be not only avoided, but also equipment weight and occupation space are reduced, and the equipment use rate is improved.