Magnetic field measurement in a strong electric field environment such as a lightning strike is one of the difficulties in electromagnetic pulse measurement technology. The traditional shielded small-loop antenna introduces radial asymmetry due to the output end structure, and it is difficult to avoid electric field interference. In response to this, this paper has developed a pulsed magnetic field sensor based on a dual-loop differential structure, which is composed of a dual-loop antenna and an optical transmission system. According to the distribution electromagnetic characteristics of the near-field, the dual-loop antenna chooses to be placed in parallel mirror symmetry, so that the terminal voltage can be divided into the magnetic field response component and the electric field response component, and then the electric field response component is removed by the differential circuit to obtain the pure magnetic field response component. Experiments have shown that in the nearby lightning strike electromagnetic field environment simulator, the dual-loop sensor has stronger anti-interference capability than the single-loop sensor, and can achieve accurate magnetic field measurement.