Abstract: At present, there are a large number of high-frequency transient current components in smart grid and new power system. High-frequency transient current is an important information reflecting the disturbance and fault process of power system, and the real-time observation of its waveform, frequency, amplitude and other information parameters is the premise to prevent and ensure the safe and stable operation of power grid. However, the traditional current measurement method has some problems, such as narrow frequency band, susceptibility to electromagnetic interference and difficulty in insulation coordination, which makes it difficult to effectively detect the transient current. Therefore, a solenoid broadband optical current sensor with anti-interference ability is proposed and designed in this paper. Based on the sensor performance test platform, the sensitivity, linearity and frequency characteristics of the sensor are studied. The results show that the sensitivity of the current sensor is 62.57 mV/A and the bandwidth can reach more than 1 MHz. In addition, a DC arc experimental platform was built to measure the DC arc. The experimental results show that the sensor can effectively measure DC to the high-frequency arc components, the linear correlation between the measurement results and the standard current probe can reach 0.9971, and the relative change rate of the correlation coefficient of many experimental results is less than 2%, which has a certain engineering value.