Based on the detailed structural finite element model of a heavy electric locomotive cab, the natural frequency of cab structure was calculated and analyzed. The acoustic FEM was applied to simulate cavity acoustic modes, and sound pressure response of frequency range from 6.3 Hz to 200 Hz at sound field was given based on wheel-rail vertical random excitation. The results indicated that the natural frequency of cab structure was intensive, and mainly in low-frequency range below 80 Hz. For the present cab, zero-pressure section line of acoustic mode made driver’s ears under a small region of sound pressure amplitude in a wide range. The zero-pressure section line was offset slightly by wheel-rail vertical random excitation at speed 100 km/h. The noise characteristics of frequency range from 100 Hz to 200 Hz in cab were significantly improved by damping and sound-absorbing material.