A simulating circuit for simulating a toggle magnetic tunneling junction (MTJ) element includes at least a synthetic Anti-Ferromagnetic free layer, a tunnel barrier layer, and a synthetic Anti-Ferromagnetic pinned layer. The simulating circuit is configured with a converting circuit, a status circuit, a storage circuit, a voltage computing circuit and a feature simulating circuit. The convert circuit converts the magnetic filed generated from a write in current to an equivalent voltage. The status circuit indicates the flipping status of the magnetic moment of the free layer. The storage circuit is used for representing data stored in the toggle magnetic tunneling junction element. The arrangement of the magnetic moment of the two Anti-Ferromagnetic adjacent to the tunnel barrier layer is represented by the voltage computing circuit. The voltage-current characteristic is represented by the feature simulating circuit.