We propose a spatiotemporal modulation method to achieve super-resolution imaging at a depletion power two orders of magnitude lower than traditional counterpart. By increasing the pulse interval between excitation and depletion lasers, the fluorescence lifetime data contain the spatiotemporal information of confocal and STED photons at the same time. Two kinds of information are bounded by depletion pulse in a period of the pulse trains, and their intensity difference represents the stimulated emission intensity by donut-shaped depletion laser. Finally, low-power STED imaging with high image quality is realized by subtracting the enhanced stimulated emission intensity from the confocal one.