A current sensor based global maximum power point tracking (GMPPT) algorithm of photovoltaic system is proposed in this article to increase the tracking speed during partial shading condition. For the proposed algorithm, the tracking range of duty cycle is reduced by calculating both the upper limit and lower limit of duty cycle and skipping the duty cycle section without global maximum power point. Compared with maximum power trapezium (MPT) algorithm and the combination algorithm of MPT and search-skip-judge, the proposed algorithm reduces the tracking range of duty cycle during both tracking directions and only needs one current sensor to realize control. As a result, the proposed algorithm shows advantages of fast tracking speed, small energy loss, and low hardware cost. Followed by theoretical analysis, the simulation and experimental evaluation validate the claimed advantages of the proposed GMPPT algorithm.