In modern tunneling construction, the blasting seismic effect seriously threatens the safety and stability of the existing engineering construction. Meanwhile, due to the complexity of blasting loading, there is a very large difference from real blasting by using the sample triangle dynamic loading model or trapezoid dynamic loading model to analyze the blasting vibration problem. In this paper, based on the analysis of the pressure change, volume expansion, fracture development, and blasting gas motion, an accurate blasting loading model was proposed. Then, adopting plane longitudinal shock theory, the coupled loading of multiple holes can be obtained. Subsequently, the 3D simulation analysis of the tunnel blasting shows an error of 2% compared with on-site monitoring data, meeting engineering requirements. Finally, based on the simulation results, regression prediction function of the velocity curve and effective tensile stress curve under different safety criteria are established, achieving accurate prediction of the damage degree of the host rock and liner line under different engineering requirements.