Abstract: Overbreak and underbreak as well as rock over-damage might occur if drilling and blasting is adopted during the tunnel construction in complex stratified rock mass, not only will it affect the construction progress and cost but also threaten the safety of constructers and tunnel stability. Taking a road tunnel passing through stratified sandstone in southwest China as the background, a research on optimization of blasting parameters is conducted by software LSPP in light of the geological conditions and lithology of the tunnel, and an optimal blasting scheme for the tunnel in sandstone is obtained. The practical application results show the optimized blasting scheme can effectively control the tunnel overbreak and underbreak.