Terahertz (THz) near-field imaging technology is always a main research branch in the THz field, because it retains the properties of THz radiation and realizes a sub-wavelength spatial resolution. In this work, a new THz near-field technique was developed. THz near-field signals were modulated and measured by two mutually perpendicular air-plasma dynamic apertures above a sample surface. A THz near-field image was successfully obtained and the sample surface was not approached by any THz detectors or sources. The performances of the imaging technique were checked and analyzed. Its advantages were expected to accelerate the advancement of THz microscopy.