According to the blasting monitoring of the main tunnel at hidden digging section of Tuandao Second Road exiting ramp in Kiaochow Bay Cross-harbor Tunnel, the paper shows the influence of vibration on the close-spaced main tunnel. Based on the monitoring results of vibration velocity and vibration frequency in the vertical, horizontal radial and tangential direction, we find that the maximum value of vibration velocity in the main tunnel appears in the range of 5-20m in the rear of the ramp corresponding work face. The magnifying effect of the vibration velocity in the rear of the work face is more obvious than the front in the horizontal radial and tangential direction, and the attenuate effect appears in the front in the vertical direction. The attenuate effect of horizontal radial vibration frequency in the main tunnel appears in the rear of ramp work face. The attenuate effect of vertical frequency in the excavated section is more obvious than the unexcavated.