This is a cauterization-resistant Magnesium and Aluminum complex material and the preparation method. Concretely speaking, this is a method that appending some low melting point materials such as Zinc, Stannum into Magnesium , Aluminum, Mg-Al alloys, Magnesium alloys and Aluminum alloys, and the make low melting point materials and Magnesium or Aluminum functionary, at the 200~500 Deg.C, at a invariable air pressure of 0~50MPa or 0~200MPa in a condition that they are enwrapped and interred by some inert materials such as graphite, alumina or magnesia, and at a heat preservation of 20~50 minutes, forming a preparation of a complex material by the connective layer between Magnesium and Aluminum, Magnesium alloys and Aluminum, Magnesium and Aluminum alloys, or Magnesium alloys and Aluminum alloys. This complex material has excellent cauterization-resistant, shade- resistant, electromagnetism- resistant and modifiable capability. This technology is simple, the quality of the production is steady, it is easy to control, low cost, and it can suit to batch-production in industry.