In order to improve the X-ray intensity of wire target driven by picosecond laser, a method of backlighting of static step wedge target by X-ray source generated by picosecond laser irradiating side radiation of self-sustaining independent wire target is proposed firstly, and experimental research is carried out on picosecond beam of the XGIII laser facility, China Academy of Engineering Physics. In this method, a picosecond laser is used to incident at 30° away from the target normal, and the X-ray source is generated by interacting of a laser with molybdenum and gold wire targets with a diameter of 10 μm. The X-ray source focal spot is measured by a multi-hole array pinhole and a CCD camera. The minimum transverse size of the focal spot of the X-ray source obtained is about 20 μm, and the longitudinal size is about 10 μm. The optimal spatial resolution of static target imaging is close to ~11 μm, which is comparable to the diameter of the wire target. The experimental results show that using the self-sustaining independent wire target side can obtain strong penetrability microfocus X-ray source. This method can provide reference for the research and application of high-energy density material dynamic process diagnosis.