The invention discloses a PPO/PA (poly phenylene oxide-polyamide) composite material and a preparation method thereof. The product is prepared by performing melt blending on PPO and semi-aromatic PA6I. Since molecular structures of the two components have benzene ring structures, organic compatibility among molecules can be achieved, and a compatibility problem is solved without an additional compatilizer. Meanwhile, the PA6I is low in melting temperature and excellent in transparency, and after the PA6I of a certain ratio is added into the PPO, the transparency and processing fluidity of thePPO can be improved. Compared with the conventional PPO/PA having basically equivalent product properties such as tensile strength, bending strength, impact strength, processing fluidity, heat resistance and the like, the PPO/PA composite material disclosed by the invention has the advantages that any compatilizer is not needed, the prepared product has excellent transparency, products with transparency requirements can be prepared, but the PPO/PA composite material disclosed by the invention is completely opaque.