Atomic force microscope (AFM) is a powerful and novel tool to investigate the surface and submembranous structures of living cells under physiological conditions at high resolution, and has force measure at nano-Newton level. AFM can image and manipulate samples (single macromolecule, cells, and so on) at very high, sometimes atomic resolution by scanning a fine tip over the surface of interest and detecting physical interactions between the tip and sample. Actin is one of the most important proteins, involved extensively in various cell physiological activities and functions in eukaryotes. The present paper clarified the crucial significance and the enormous applicable prospects of AFM in modern biological sciences by reviewing the usage of AFM in actin study, which can be taken as a good example for expounding almost all functions that AFM owns, and can be utilized in life sciences exploration.