The ultrasonic assisted extraction technique was employed to obtain phenolics from CWCP and different factors on the phenolics yield were considered, including the solvent type, ratio of liquid to solid, extracting temperature, ultrasonic power and ultrasonic time. Based on the single factor tests, an appropriate solvent for more consistent extraction of phenolic compounds would be defined, and response surface experiments would be used to optimize the extraction parameters. The results showed that the optimum conditions for total phenolic extraction were determined: ratio of methanol to solid 1∶15 (g/mL), extracting at 55 ℃ for 55 min with, ultrasonic power 270 W. Under the control of these conditions, the yield of total phenolic content (TPC) was 4.42 mg/g. The optimum conditions for total flavonoid extraction were shown as ratio of methanol to solid 1∶20 (g/mL), extracting temperature 60 ℃, ultrasonic power 240 W and ultrasonic time 55 min and the yield of total flavonoid content (TFC) was 15.20 mg/g under these conditions.