Due to the diffraction limit, it is difficult to achieve far-field super-resolution focusing and imaging for traditional optical systems. The appearance of planar superlenses based on the super-oscillation principle provides a possible solution to the problem. It can achieve far-field super-resolution focus without using evanescent waves. By precisely adjusting the diffraction and interference effects among the diffractive elements, electric field oscillation that is higher than the highest spatial frequency of the system can be measured in the local area of the focal plane, and thus the transverse and axial sizes of the diffractive focal spot can be precisely controlled. Compared with conventional optical lenses, planar Super-Oscillatory Lenses(SOLs) hold advantages for their arbitrary control over the optical field, large degree of freedom in design and easy integration with optical systems. Due to the above-mentioned reasons, SOLs have attracted extensive attention from researchers in the fields of diffractive optics and micro-nano optics. In this paper, concerning practical applications, the research state-of-the-art and application scenarios of planar SOLs are presented and discussed. Finally, the system's problems and its corresponding solutions are also described.