Objective: To optimize acid enzymatic extraction process of soluble dietary fiber from Passiflora edulis peel and provide references for research and development of its functional food. Method: Based on single factor tests

with the concentration of citric acid solution

solid-liquid ratio

thermostable alpha amylase dosage

reaction temperature of complex enzyme as independent variables

extracting amount of soluble dietary fiber as dependent variable

Box-Behnken response surface methodology was used to optimize extraction conditions. Result: Optimum process conditions were as follows:solid-liquid ratio of 1:40

thermostable alpha amylase dosage of 5.0 U·g-1

the concentration of citric acid solution of 0.18% and reaction temperature of complex enzyme at 80 ℃.Yield of souble dietary fiber was 13.82%

whose relative error was -6.56% by comparing with the predictive value. Conclusion: Optimization of extraction process of souble dietary fiber from P. edulis peel by response surface methodology is accurate and reliable with some practical value.