In life science research, it is often required to localize proteins in a live cell to a certain accuracy to study their localization-related function. However, due to the Abbe/Rayleigh criteria of light, the widely used wide-field/confocal microscopy can never resolve structures less than 200 nm in diameter. In recent year, different super-resolution microscopy techniques emerge as a result of new fluorescent probes and imaging theories. A full frame to the theories and recent advancements in this field is summarized. The concept of point-spread function of light source in the focal plane and the classical definition of resolution is explained in the first part. The fluorescence single-molecular imaging technique and the equation that defines the localization accuracy of a single molecule is introduced in the second part. Based on these knowledge, super-resolution microscopy methods based on single-molecular imaging technique, such as photoactivated localization microscopy (PALM) and stochastic optical reconstruction microscopy (STORM) is discussed further. On the other hand, by engineering the point spread function of the light source, super-resolution can also be achieved. Two typical methods, stimulated emission depletion (STED) and saturated structure illumination microscopy (SSIM) are explored thereafter. In the end, different methods to extract super-resolutional information along the z axis, and their combinations with the methods to increase xy plane resolution mentioned above are explained. In the end, the limitation to the current super-resolution methods and their future direction are also discussed.