通过对尾隙角的分析研究，提出了作用尾隙角的概念，给出了作用尾隙角的计算方法，研究了刃磨参数对作用尾隙角的影响．给出了作用尾隙角在数控刃磨求取刃磨参数中的应用方法．研究表明，尾隙角是关系到钻头钻削性能的重要参数，数控刃磨中的几个刃磨参数对它的影响程度由大至小的次序为θ、Ｃｙ、σ、ω、Ｃｘ． Through the analysis of tail clearance angle, the concept of tail clearance angle is put forward. The calculation method of tail clearance angle is given and the influence of grinding parameters on the play tail clearance angle is studied. The application of the function of backlash angle in sharpening parameters of NC sharpening is given. The results show that the clearance angle is an important parameter that relates to the drilling performance of the bit. The order of influence of several parameters on the sharpening is θ, Cy, σ, ω and Cx.