In order to get rock sampling in planetary exploration program. A vibro-impact drilling device based on the ultrasonic/acoustic energy coupling mechanism is presented, structural dynamics analysis and parametric design of which are carried out . Considering contact boundary conditions, the ultrasonic/sonicimpact dynamics model, which uses dynamic explicit to analyse the stress in drilling process, is established. According to the results of analysis, the experiments of the modal test and the movement of free mass using high-speed photography system are carried out. The relationship between the motion of the free mass and the drilling performance can be got. The drilling experiments show that it can get rock sampling well in planetary exploration program with a suitable free mass.