Abstract: Influences of filter cut-off frequency , by which fine rough surface characteristics can be further achieved after obtaining rough surface roughness , on contact mechanism for rough point contact were investigated with authors contact program based on FFT technology and conjugate gradient method Numerical results show that the cut-off frequency used for has a significant effect on curve of applied force against approach between the two contacting bodies The smaller cut-off frequency , the larger contact area and the smaller contact pressure It 15 also found that the cut-off frequency can change magnitude and distribution of Von Mises stress in contacting bodies , especially those in contacting surface Therefore , it is necessary to reasonably chose cut-off frequency so as to correctly evaluate the point contact mechanism