介绍了一种可以得到直观刀具刃形的近似作图法，通过几何图形的分析，引出了环形带宽的概念，并在此基础上，利用拉格朗日定理和矩阵方程求解铣刀刃形。通过实际计算和试验，证明这种方法是可行的，较空间啮合法设计铣削阿基米德螺旋面成形铣刀方法具有一定的优越性。 This paper introduces an approximate drawing method which can get the knife edge of the tool. Through the analysis of the geometric figure, the concept of the annular bandwidth is introduced. On the basis of this, the cutter edge shape is solved by Lagrange theorem and matrix equation. It is proved that this method is feasible by the actual calculation and experiment. It has some advantages over the method of designing and milling Archimedes spiral face milling cutter.