Abstract: Since fruit texture differs completely from other tissues such as leaf, root and flower due to its unique properties, the method for mitochondrion extraction is different. Using a special grater to grind the fruits, combination with gradient centrifugation, mitochondria with much higher activity can be obtained. The Broth er oxygen electrode was introduced to judge whether the mitochondrion membrane was intact or not. In addition, PAGE gel electrophoresis and Western Blot (AOX monoclonal antibody) were used in this paper to isolate and identify AOX in Royal Gala apple fruits. The results suggested that these proteins have apparent molecular masses of 35～37 kD which are similar to those of Tobacco andSauromatum guttatum Schott.