Abstract: The effect of combined ultrasonic-cellulase extraction on the extraction amount of procyanidins (PCs) from chestnut shell and the antioxidant activity of the extract was analyzed. The optimization of PCs extraction from chestnut shell by ultrasound and cellulase extraction condition were investigated by single factor and orthogonal experiments. Furthermore, the effects of ultrasonic-assisted extraction, cellulase-assisted extraction, and their sequential and simultaneous combinations on the extraction efficiencies of PCs and the antioxidant activities of the resulting extracts were evaluated. The results showed that the extraction amount of PCs obtained by ultrasonic and cellulase extraction methods under the optimal extraction conditions were 21.03 mg/g and 10.12 mg/g, respectively. The extraction amount of PCs obtained by ultrasonic-cellulase extraction and cellulase-ultrasonic extration were 23.58 and 19.04 mg/g, respectively. The simultaneous ultrasonic and enzymatic treatment could obtain the highest conten of PCs, which was 26.46 mg/g. Furthermore, the DPPH radical scavenging ability and hydroxyl radical scavenging ability of the obtained extracts was also the highest, with values of 74.11% and 55.21%, respectively. This research results confirmed that the extraction amount of PCs obtained by ultrasonic and cellulase methods was the highest and the antioxidant activities of the extract was the best. It provided reliable theory basis for the recycling of chestnut shell.