The invention provides a blasting excavation method for a tunnel, which is applied to the technical field of the tunnel excavation technology. The blasting excavation method for the tunnel comprises blasting steps as follows: a presplit hole group (3) is arranged in the position, close to an underground pipeline (2), of a blasting surface (1), a smooth hole group (4) and cutting hole groups (5) are further arranged in the blasting surface (1), and explosives are charged into presplit holes of the presplit hole group (3), smooth holes of the smooth hole group (4) and cutting holes in the cutting hole groups (5) respectively; the presplit hole group (3) is detonated firstly, then the cutting hole groups (5) are detonated, and the smooth hole group (4) is detonated finally. According to the blasting excavation method for the tunnel, the steps are simple, blasting excavation cost of the tunnel cannot be increased, blasting vibration in the tunnel excavation process can be weakened from thesource in the blasting excavation process of the tunnel, so that an urban underground pipeline is effectively prevented from being damaged due to the blasting vibration, and finally, not only is smooth operation of blasting excavation work guaranteed, but also the underground pipeline is effectively protected.