Fast imaging techniques have important applications in many fields. An ultra fast surface microscopic imaging technique is proposed and demonstrated. This technique is based on the time space frequency mapping of ultrashort optical pulses. Based on dispersive Fourier transform and spatial dispersion devices, the optical spectrum is mapping on time and space domain separately. The image is reconstructed after a high speed serial single pixel photo detector. A one and two dimensional imaging system with the frame rate of 20.9 MHz, 22 μm and 55 μm spatial resolution is realized. Imaging experiments with standard resolution targets are successfully demonstrated. This technique is an effective method for ultrafast imaging and can be used for high speed surface inspection.