This work focused on optimization of ethanol fermentation of yeast cells immobilized by calcium alginate-chitosan (ACA) using orthogonal experiments. Alcoholicity of original cider was used as an evaluating indicator. The single factor tests indicated that fermentation factors, starting sugar content, inoculating quantity of yeast, initial pH and fermentation temperature, had different effect on ethanol yield. L9(34) orthogonal tests showed that the optimal conditions of cider fermentation were as followed: inoculating quantity (percentage of amount of ACA-yeast biocatalyst to volume of apple juice, g/mL) 4%, starting sugar content 20 °Bx, fermentation temperature 26 °C, initial pH 2.5. The verification experiments suggested the alcoholicity of original cider reached 10.9% under the optimal conditions.