The Stress Concentration Factor (SCF) of the tubular joints of wind turbine foundation under the action of axial force, in-plane bending moment and out of plane bending moment is high, which often leads to the fatigue limit state of multi-pile foundation offshore wind turbine structure becoming its critical design state. Therefore, it is necessary to carry out further research on this problem. To address this issue, a method of setting stiffener ring and extra stiffening plate parallel to the chord axial direction is adopted to control SCF. This method has the characteristics of simple design and easy construction. The finite element simulation software ANSYS is used to analyze the three-plane Y-shaped tubular joints. The results show that several methods of stiffening member can reduce SCF and the method has practical value in engineering.