Now, pneumatic rotary anchor roofbolter is widely used in the underground. Pneumatic rock driller is mainly operated in hard rock tunnel, but it often exists in the phenomenon of hard rock and soft rock sections alternately. The result is occured in the replacement of drilling rigs and drilling tools, to produce a great deal of inconvenience. This not only affects seriously anchorage operating speed, but also increases production costs and brings insecurities factors of replacing driller. This study analyzes the performance and parameters of traditional rock rigs & roofbolter. Mechanical Model is established on the basis of studying rock breaking mechanism. Drilling parameters are comprehensively evaluated. It is put forword of specific rotary-impact function of pneumatic anchor rock driller. On this basis, specific rotary-impact function of pneumatic anchor rock driller has been systematically studied.