Abstract: Measuring technology and data processing method of two-path optical current sensor were proposed. High pulse current could be measured by two-path configuration and arc-tangential function processing method with the constant output power of laser. The electric guns short current was contrastively measured by two-path optical current sensor and Rogowski coil at 18 kV voltage, 31.8 F capacity. The experimental result of optical current sensor agreed well with that of Rogowski coil. It proves that two-path optical current sensor can be used to measure high pulse current effectively.