Abstract: To explore the influence of track bed vertical irregularity on vibration source intensity, multi-body system dynamics analysis method is applied to simulate vehicle-track coupling dynamics, and finite element method is adopted to establish flexible body model. The track bed vertical irregularity is obtained by simulating the cosine function of the different irregularity amplitudes and irregularity wavelengths on flexible rail. The vibration source intensity data of positions such as track bed slab and tunnel wall are extracted and analyzed. Research shows that the peak value of tunnel wall vertical acceleration mainly concentrates in the region of low-frequency within 100 Hz, and track bed rising has relatively evident influence on vibration source intensity, in which the working condition of track bed expansion joint at the slab rising center is the most influential.