An elastic actuator is provided, which may include a position motor and an electromagnetic spring. The position motor may include a motor output shaft. The electromagnetic spring may include a rotor, a stator and a gear set. The stator may drive the rotor to rotate. The gear set may include a first output shaft, a second output shaft and an output shaft; the first input shaft may connect the motor output shaft, and the second input may connect to the rotor. The power generated by the rotor and the power generated by the position motor may be outputted from the output shaft after being coupled via the gear set.