Blast-induced rock damage and overbreak in tunneling construction may result in increasing construction costs and declining the stability of tunnel. In this paper, the rock mass behavior induced by tunnel blasting is analyzed by using numerical analysis based on continuum damage mechanics and fuzzy-random probability theory so that the degree of damage in remaining rock and overbreak can be estimated. An equation to estimate the blasting pressure is derived from the application of shock wave theory; statistical analysis is also performed to systematically assess the uncertainty of the proposed pressure equation. A numerical continuum damage model is proposed to assess the rock mass behavior induced by tunnel blasting. The proposed model is coded and linked to a commercial software ABAQUS/Explicit through user subroutine. The result of numerical analysis showed that the degree of overbreak can be reasonably evaluated by adopting the concept of fuzzy-failure probability.