All hydraulic drill power-head used in coal mine is mainly composed of hydraulic motor and gearbox, and the vibration intensity of gear transmission directly affects the output capability of power-head. Take ZYWL-2600R soft coal seam spiral drill as the research object, on the basis of single degree of freedom torsion vibration model of gear pair, the vibration acceleration of meshing line as optimization objective, a dynamic optimization design model of power-head gear pair is established and the graphical interface of the optimization program is developed with the help of Matlab optimization toolbox and GUI tools to figure out the minimum macroscopic design parameters of vibration, which provides the reference to dynamic optimization design of high speed drill power-head. The results show that the gear mesh stiffness of the optimized gear pair is significantly increased accompanied with the effective improvement of vibration characteristics of gear transmission.