In order to improve the measuring precision and controling precision of the Line Edge Roughness (LER) in microelectronics fabrication technologies,the influence factors of LER measure-ments for semiconductors using Atomic Force Microscope(AFM) is studied.Firstly,the LER features are extracted from an AFM image of single crystal silicon based on image processing techniques,and the parameters are determined to quantitatively characterize the LER features.Then,according to the characteristics of LER measurement and characterization method,the influence factors of LER measurements using AFM,including the nonideal properties of the sizes and shapes of probe tips,the signal noises of AFM images,scan sampling intervals,the driving precision of piezoelectricity,cantilever oscillation and the free parameters of edge detection algorithm and so on,are analyzed theoretically and experimentally,and the methods for restraining and amending the measuring errors are respectively proposed.The study indicates that a more precise measurement result for LERs using AFM can be obtained by eliminating or reducing the influences of various factors on measuring errors by proposed methods,which can provide a theoretical and methodologic support for improving the accuracy of nanometer-scale line structure topographic measurement.