Abstract: The imaging resolution of a conventional optical microscope is limited to 200nm by the diffraction in the visible spectrum. In order to overcome the resolution limit of the imaging, the microsphere combing with the traditional optical microscope was used to obtain the super-resolution imaging in far field. Firstly, the transport of the object light waves in the air was analyzed theoretically after the parallel light interacted with the micro-nano structure object, and the mechanism of the far-field super-resolution imaging was analyzed that the evanescent wave was converted into the transmission wave by the microsphere. Secondly, the photonic nanojet characteristics of the microspheres were researched. The results show that the radius of the photonic nanojet by the microsphere is less than half of the incident wavelength. Lastly, the blue-ray disc was used as the object, the experimental system of the super-resolution imaging based on the microsphere combining with traditional optical microscope was set up. The resolution of the imaging system is 100nm in the far-field. The results show that the imaging system can be used in the detection of the micro-nano structure. The results are helpful to the lithography, bio-medicine, etc.