To simulate the complex morphology of steel plate and obtain the fatigue notch factor based on real surface topography, the Q235 steel plate was corroded rapidly by salt spray method, and the corrosion surface was measured by three dimensional measurement. Three-dimensional solid model was established, and the surface stress distribution was analyzed by reverse engineering Geomagic Studio software and numerical analysis software ANSYS. Then the numerical results and experimental results were compared. The results show that the error is small enough, which verifies the feasibility of the modeling methods. Geomagic studio can achieve a rapid 3D visual modeling and simulate the corrosion morphology well, combined with ANSYS, it can estimate the fatigue notch factors of various complex morphology components flexibly and efficiently.