A bistable switching method and a latching relay using the same are provided. The latching relay includes a rotor shaft, a cylindrical permanent magnet, a first permeability material, a second permeability material, a coil, a hitting device and a contact unit. The method includes the following steps. While the coil is applied first direction currents, the rotor shaft rotates and to make the contact unit from the open state to the closed state or the contact unit keeps the closed state. After the first direction currents are turned off, the contact unit still remains in the closed state. Otherwise, while the coil is applied second direction currents, the rotor shaft rotates and to make the contact unit from the closed state to the open state or the contact unit keeps the open state. After the second direction currents are turned off, the contact unit still remains in the open state.