The bedrock/boulders along the alignment of shield tunneling cannot be excavated directly by the cutterhead of the shield, therefore they have to be treated in advance. In the construction of the diversion tunnel of Taishan Nuclear Plant in Guangdong, China, the bedrock/boulders along the tunnel alignment have to be blasted in advance. In the paper, the unit consumption of the explosives for the blasting is studied by means of theoretical deduction and field test and a calculation formula is obtained. The formula has been used in the engineering practice and good result has been achieved.