The power efficiency of MOS charge pumping circuit is becoming one of the most important issues as the power supply decreasing continuously and the area of a chip. Owing to the threshold voltage losing of the transfer MOS, power-efficiency of traditional Dickson charge pumping is low. In this paper, a high-efficiency two-phase charge pumping circuit bases on the four-phase are invented, which solves the contradiction between the power-efficiency and the chip area consequently.