In order to solve the problem of low frequency vibration and noise of interior panel structure of highspeed train, a "cap type" phononic crystal structure was designed based on local resonance mechanism. Based on the finite element method, the "cap type" phononic crystal unit model was established, and the energy band structure of the unit cell was calculated, and the complete band gap of 183.35~245.14 Hz was obtained. Then, combined with the interior panel, the model of periodically arranged "cap type" phononic crystal trim panel was established. The vibration and sound radiation characteristics of the phononic crystal trim panel under the vertical unit concentrated force excitation and the sound insulation characteristics under the background sound field excitation were analyzed, and the influence of the damping of the trim panel on the sound and vibration characteristics of the phononic crystal trim panel was explored. The results show that: compared with the ordinary trim panel, the vibration acoustic radiation characteristics of the trim panel of phononic crystal have a better suppression effect in the band gap range of 180~210 Hz, and it has a better sound insulation characteristics in the frequency range of 10~500 Hz; the damping loss factor has a more obvious effect on improving some weak points of the acoustic vibration characteristics of the phononic crystal trim panel, which can significantly suppress the vibration control vibration sound radiation peak point and improve sound insulation trough point.