The purpose of this paper is to obtain the optimum conditions for extracting nobiletin from sweet orange residue after squeezing juice with the assistance of ultrasonic.On the basis of single factor experiments,the Box-Behnken experimental design and the response surface methodology were used to optimize nobiletin yield depending on the solid/solvent ratio,the treatment temperature,the treatment time and the ultrasonic power.Results showed that regression equation for nobiletin yield exhibited tremendous si...