The invention provides an AFM probe lateral force calibrating coefficient measurement method and a lateral force calibrating method, and belongs to the crossing field of nano-technology and nano-tribology. The measurement method is conducted in the environment condition of a standard laboratory. By means of an AFM, the friction electrical signal Uf and the surface adhesion Fad of a test specimen in the same region under the effects of different normal loads are measured. After that, the measured values are substituted into Uf beta = k (Fn + Fad). In this way, a lateral force calibrating coefficient beta is figured out through the optimal parameter estimation method, so that the calibrating process of the lateral force is realized. According to the technical scheme of the invention, the materials of the above method are optional, convenient to obtain, low in cost and free from being processed. Meanwhile, the above method is provided based on the law of Amontons, so that the influence of the adhesion on the calibration is fully considered. The calculation process is simple, quick and accurate, so that the method can be widely used for calibrating the lateral forces of various AFM probes and micro-cantilevers.