Abstract: In measuring topography of sample, the interaction between tip and sample will cause the deformation on the sample surface and the deformations will be different in the regions with different mechanical property. Furthermore, the deformations will cause non-negligible error in topography measurement. Theory analyses are carried out on this measurement error and further numerical research shows that mixed signals with high-frequency components are able to eliminate the measurement error. However, it is difficult to measure high-frequency signal for normal cantilever. In order to gain a proper high-frequency signal, a modified cantilever is introduced. The new designed cantilever can help us to adjust the relative values of eigen-frequencies of a cantilever and then enhance the high-frequency signal.