Abstract: Based on contact fractal theory, a fractal model of contact stiffness was discussed. The stress concentration on the hole edges was found with a finite element analysis about stress distributing of the low-speed heavy-duty equipment shaft and flange. The experiments which can validate the reliability of the FEM simulation analysis and avoid collapsed phenomena on the hole edges were done. The results of the experiments are consistent with the FEM simulation analysis, and they provide reliable basis for the design of the low-speed heavy-duty equipment.