Abstract: Twoslope method, which is used to calculate the materials' elastic modulus and hardness by using of nanoindentation forcedisplacement curves, was modified by the introduction of two correction parameters that account for the effect of the two factors that influence the accuracy of this method most severely. The values of the correction parameters indentation on fused silica with Berkovich indenter were obtained by FEM simulation and comparison between the experiments and standard values of fused silica. Good agreements between the values from the two ways demonstrate the capability of the modified twoslope method, and the insensitivity of the twoslope method to the wear of the indenter tip.