This paper presents a current sensor for current measurement in high frequency high voltage pulse power supplies, the output of which is DC current superposed with impulse current waveform. The current sensor is made of two magnetic cores. One works in fluxgate principle to measure DC current. While the other is based on transformer effects for impulse current measurement. The impulse current sensor has a wide bandwidth up to 340kHz. It can measure DC with an accuracy of about 3%o, and the measurement errors for impulse current peak is limited to 6%.