The invention relates to a nanometer air guide fiber membrane for improving fiber composite material appearance and a preparation method and application thereof. The nanometer air guide fiber membrane comprises release layers which are arranged on the upper surface and the lower surface respectively, a nanometer air guide membrane layer and a fiber cloth layer which are arranged between the upper release layer and the lower release layer. According to the nanometer air guide fiber membrane for improving the fiber composite material appearance, the phenomena that the appearance in the original product is out of flatness, lack of glue and has pinholes are overcome, excess gas is exported by the nanometer air guide membrane, at the same time, by means of the composite structure of the nanometer air guide membrane and the fiber cloth, the introduction of the gas between layers is effectively reduced, the preparation method is simple, the technological process is short, the forming way is diversified, and it is beneficial to obtaining a full and smooth appearance, the quality and yield rate of the product are improved.