Abstract: Aiming at the efficiency problem of rock breaking by drilling rig in deep hole drilling of underground coal mine, combined with the experimental data of domestic screw motor of 77 millimeters, we use SPSS multivariate regression analysis principle and model to analyze the influential factors. It was shown that the screw motor drilling rate met a nearly linear relationship with the flow rate or pump pressure, and the screw motor speed equation was built which had a high accuracy with the average relative error of 5.28% in forecasting screw motor drilling rate. An optimizing parameters method for km drilling rig is proposed, which has certain theoretical guiding significance for actual deep holes drilling.