This paper aims to present an additional structure based on acoustic metamaterial for reducing the vibro-acoustic transfer function of a car body panel. As a vehicle becomes lighter and an excitation force becomes bigger due to high performance engine, it has become more difficult to minimize the vibration and noise transfer through body panels by using conventional NVH countermeasures. In this research, a new approach based on acoustic metamaterial is tried to reduce the vibration and noise transfer of firewall panel. First, a unit cell structure based on the local resonant type of acoustic metamaterial is devised and the design variables of a unit cell are optimized to have strong wave attenuation in the stop band of a dispersion curve, where the theorem of Bloch equation is used to estimate the response of a two-dimensional periodic system. Also, the vibration transfer and the radiated sound power are predicted with a FE model of meta-plate which is composed of periodic system of the devised unit cell. Next, the transmission loss of the meta-plate is tested in a mini anechoic chamber and its design is revised for the better acoustic performance and feasible application to a vehicle. Finally, the revised structures which are respectively mounted on firewall are tested to verify the vibro-acoustic transfer characteristics of firewall. As a result, it is shown that the suggested meta-plate structure has a good effect on reducing noise transfer though a car body panel.