To address lack of reliable power supplies for lightning current measurement systems (LCMSs), this paper proposes a novel type of self-powered LCMS. The required operational power consumption of the LCMS can be harvested using a power coil from the large lightning current which is being measured such that the system can be energized to complete a single-cycle signal measurement and data record. The polarity, current peak can be measured using a specially designed two-channel peak holding circuit as low-power substitution of conventional high-speed sampling modules, and thereafter with trigger time, the three parameters of lightning currents can be ultimately stored in non-volatile memory. The paper presents theoretical and simulation studies to determine structure, size, number of winding turns of the power and signal coils. Besides, the circuitry design of the power supply and signal conditioning units are also addressed. Experimental results prove that the proposed LCMS can accurately measuring amplitudes of lightning currents, with an error of less than 4% being achieved, while the system is fully self-powered to satisfy energy demand from the transient measurement and record of lightning current parameters.