The invention discloses a microresistivity scanning imaging logging device and a radiating circuit thereof. The radiating circuit comprises a filter module, a power amplifier module, a boosting module, a current measuring module and a voltage measuring module, wherein the filer module is used for receiving alternating current electrical signals and smoothing the alternating current electrical signals; the power amplifier module is used for amplifying filtered alternating current electrical signals; the boosting module is used for boosting amplified alternating current electrical signals to generate and output radiating signals; the current measuring module is used for measuring the electricity of the radiating signals and outputting measured current data; the voltage measuring module is used for measuring the voltage of the radiating signals and outputting measured voltage data. According to the invention, radiating signals which are large enough can be outputted to enable the radiating signals to penetrate through a mud insulating layer or a mud cake between an electrode and a borehole wall to enter into a stratum; the microresistivity scanning imaging logging device is suitable for microresistivity scanning imaging in oil bases or synthetic base mud.