Abstract: In order to better control the borehole tracing,with a study on an algorithm of the directional drilling borehole tracing in underground mine,the parameters of the borehole tracing design were obtained.According to the borehole design procedure,the design code of the borehole tracing parameters was systematically summ arized to guide the design of the borehole tracing.The site drilling was provided to the optimized method of the borehole tracing design. The tools orientation angle obtai ned from the study on the deflection law of the directional drilling was the main factor affected to the borehole tracing of the screw rod drilling tools.In combination with t he strata hardness,gravity role and other factors affected to the borehole deflection,the borehole tracing predicted method with the tools orientation angle was obtained. Finally according to the directional drilling deflection law and the construction experiences,the tools face combination to meet the requirements of the different borehole tracing control was concluded and summarized.With the rational tools face combination selected,the borehole tracing could be controlled in the construction of the targe t area.