The object of this article is to study the plausibility of applying human voice warning system to automobiles. Human voice is considered the best tool for warning system in automobiles. For the purpose of comprehending the specific characteristics of relation between noises and properties of the automobiles indoors and voice warning system researcher performed FRF test in order to examine the characteristics of voice output, and FEM simulation to learn the specific properties of the car indoors. And furthermore, surveyed the quality of voice output, using the written inquiry to examine members. The result of the study shows that it is much possible to apply voice warning system to automobiles.