Abstract: Presents the dynamic characteristic analysis of YZ-55A Blast-hole Drill's structure by using SAP5P program. The result shows that the reasonable working rotation speed range should be between 80 and 150r/min. Based on the load spectrum of YA-55 Blast-hole, the dynamic stress calculation on YZ-55A is carried out by introducing adjusting coefficient, the structure's vibration modes and strees-time histories are are presented.