Red pigment (RP) was extracted from the peels of Maxim (PZB) by ultrasonic-assisted extraction (UAE) in this work. Box⁻Behnken design⁻response surface methodology (BBD-RSM) was employed to research the efficiency of the RP extraction. Based on the optimization of RSM, results showed that the optimal extraction conditions were as follows: liquid⁻solid ratio of 31 mL/g, extraction time of 41 min, and extraction temperature of 27 °C, and under these conditions, the actual absorbance value was 0.615 ± 0.13%, highly agreeing with the predicted value by the model. Furthermore, ultra-performance liquid chromatography⁻mass spectrometry (UPLC-MS) was used to separate and analyze RP. The compounds of RP were mainly flavonoids, and there were five compounds detected for the first time in PZB. In addition, RP showed significant antioxidant activities in vitro, which could be developed for anti-aging candidate drugs and functional foods. In conclusion, ultrasound-assisted extraction with BBD-RSM and chromatographic separation technology with UPLC-MS are efficient strategies for the isolation and identification of RP from PZB.