The invention discloses a compound stabilizer for storing aspartate amino transferase mitochondria isozyme and a using method of the compound stabilizer. The activity of the aspartate amino transferase mitochondria isozyme can be kept under a liquid condition for a longer term by using the compound stabilizer. The compound stabilizer is prepared by blending and stirring the following raw materials: 0-60% of glycerin, 1-15g/L of beta-cyclodextrin, 5-20g/L of mycose and 0.5-5mol/L of inorganic salt. The using method of the compound stabilizer comprises the following steps of: heating the compound stabilizer and an enzymic preparation to a certain temperature; then, rapidly mixing the compound stabilizer and the enzymic preparation to be uniform; stirring while adding; and preserving the heat at a proper temperature for a certain time. By using the compound stabilizer, the aspartate amino transferase mitochondria isozyme can be kept stable in a solution, and the activity decaying of the aspartate amino transferase mitochondria isozyme can be decelerated. The raw materials of the compound stabilizer are easy to obtain; the activity of the aspartate amino transferase mitochondria isozyme can be kept at the temperature of 4 DEG C for 1 year; freeze-drying powder is prevented from being used; the operation steps of a diagnostic reagent are simplified; and the stability of the diagnostic reagent is ensured.