Current is one of the most basic detection indexes in power system. In addition to the measurement of basic power frequency and DC current, the measurement of impulse current in power system is also very important. Its measurement accuracy is directly related to the measurement level of power system transient over-current and the safety of equipment and personnel. In order to measure the impulse current efficiently, conveniently and accurately, a broadband magnetic field sensor based on Archimedes spiral structure is developed. Firstly, the field circuit simulation of the magnetic field sensor with Archimedes spiral structure is carried out. The sensitivity of the magnetic field sensor is greatly improved, and the capacitance to ground is 1.0578pf. The rise time of step response is 20.4ns and the overshoot is 4.5%. The simulation results show that the magnetic field sensor has excellent high frequency characteristics and dynamic response characteristics. Compared with the standard shunt of State Grid measurement center, the amplitude error is better than 0.2%, the rise time error linearity is better than 0.2%, and the half peak time error linearity is better than 0.1%.