The influences of surface roughness on the geometric morphology of rough surfaces’ profile curve were investigated.The profile curve obeying normal distribution and with preset surface roughness was simulated by the processing parameters of surface roughness and Monte Carlo random sampling.From the microgeometric characteristics of the simulated profile curves with different surface roughness,fractal geometry model was constructed with the isosceles triangle as element.The fractal dimensions under different surface roughness were calculated with the profile configuration method,and the power law relationship between the fractal dimension and surface roughness was obtained.According to the calculating data and the mathematical regression,the average peak angle and height of the isosceles triangle element in the fractal geometry model can be descripted by using the fractal dimension and fractal scale.The description formula of the rough surfaces’ geometric morphology characteristic and fractal parameter were built and used under the surface roughness from 0.1 μm to 1.6 μm.