The invention discloses an MgAl2O4-CaZrO3 (magnesium aluminate-calcium zirconate) composite mould shell as well as application and a preparation method thereof. The MgAl2O4-CaZrO3 composite mould shell is prepared from the following materials of CaZrO3, alumina-magnesia spinel, yttrium sol, silicon sol, a surfactant (stearic acid), and a defoaming agent (n-butyl alcohol); a surface layer of the mould shell is made of CaZrO3; a back surface is made of alumina-magnesia spinel. The MgAl2O4-CaZrO3 composite mould shell has the characteristics that the property of slurry is stable, the coating property is good, the storage is easy, the high temperature-resistant and heat vibration-resistant properties are good, the chemical stability is high, and the like. The prepared casting has the characteristics of thin surface pollution layer, high size accuracy and the like; the prepared casting is suitable for being applied to precision casting and oriented condensing; the fire-resistant degree is higher, the high-temperature stability, high-temperature strength and heat vibration-resistant properties are excellent, and the industry value is important.