Abstract:The research aimd to study the selection of immobilized materials of acetic acid bacteria，the fermentation characteristics and mechanical strength of immobilized bacteria，and the effects of different fermentation conditions have on the acid production of banana-passionfruit vinegar.The results showed that the banana fruit vinegar produced with corncob as immobilized material of acetic acid bacteria has the best quality，with low alcohol residue and recycle rate of 4 times after fermentation.The optimum fermentation conditions were as follows：the initial alcohol was 8°，the fermentation temperature was 35℃，the fermentation time was 6 d，the pH was 3.5.The total acidity of composite banana vinegar was 5.05%.