Abstract: This paper analyzes the rock breaking mechanism of “percussive-rotary drilling” based on the theories of solid mechanics and the stress formula of rock deformation.Besides,it offers a full review of working principle of new-type Steel Ball Percussion Tools co-developed by China and Russia and works out the relations of Percussion Tool’s parameters by analyzing the experiment data gathered in the lab and in field experiments.It is revealed that carbide-alloy(or diamond) drill bits together with steel ball percussion tools used in percussive rotary drilling leads to much improved drilling rate and reduced cost.