The invention relates to a phase modulation imaging mode scanning device of an SICM. The scanning device comprises a signal generator, a phase-locked amplifier, a patch clamp amplifier, a controller, a probe, an XY nanometer platform and a Z-direction nanometer piezoelectric ceramic. The signal generator, the patch clamp amplifier, the phase-locked amplifier and the controller are connected in sequence; the signal generator is connected with the phase-locked amplifier; and the patch clamp amplifier is connected with the probe. The method comprises the following steps: the signal generator outputs two paths of AC signals to the phase-locked amplifier and the patch clamp amplifier respectively; the compensation capacitance of the patch clamp amplifier is adjusted; the phase-locked amplifier extracts current component and feeds back the amplitude to the controller; and the controller controls the height of the probe in real time according to the amplitude, and scanning of a sample is realized. According to the phase modulation imaging mode scanning device and method, only the alternating current component under some frequency is extracted to serve as the feedback value, so that the defects of DC drifting and easy electrical noise influence under a DC mode and the like can be overcome; and compared with a conventional AC mode, the method realizes higher modulation frequency, and the purpose of accelerating scanning can be realized.