Atomic force microscope ( AFM) uses the interaction force between the probe and the object to be measured to achieve imaging, and obtains the relevant geometric parameters through obtaining the high-resolution imaging of the rectangular nano grating measurement standard instrument and performs calibration, so as to realize the quantity transfer from standard measurement instrument to working measurement instrument. In the AFM scanning process, due to the influence of the needle tip, the scanned image is the result of the interaction of the probe and the sample, rather than a true description of the sample morphology. Aiming at this phenomenon, this paper proposes an AFM image restoration method based on long short-term memory (LSTM) network. This method trains the scan lines of the simulation image obtained with the expansion method, and then obtains the AFM image restoration model suitable for rectangular nano grating. Experiment results show that for a rectangular nano-grating with a line width of 20 nm and a height of 40 nm, the relative error of the grating line width after restoration with the proposed method is 7. 40% , the proposed method further improves the measurement accuracy compared with the traditional restoration method.