Apple peel extract is a by-product of apple sauce, apple juice and other products. To investigate its probiotic properties, apple peel extract (APE) was extracted using 80% acetone. The polyphenol components of the extract were determined using high-performance liquid chromatography. Changes in biomass, pH and polyphenol components were then tracked for 24 h using in vitro anaerobic fermentation. The pH value of the fermentation broth was kept at 3.66~4.00 (42.86%~47.71% lower than that of the control group). A total of 13 types of polyphenol were identified from APE. The main polyphenols were phlorizin (515.54 mg/100 g), hyperoside (530.06 mg/100 g) and quercitrin (459.04 mg/100 g). The growth of Bifidobacterium longum, Lactobacillus acidophilus, Lactobacillus paracasei, and Lactobacillus rhamnosus was significantly promoted by the apple peel extract compared with the control group. During the fermentation process, phlorizin was consumed 93.36%, 89.21%, 86.31%, and 0.41% by each bacterium, respectively. The results showed that apple peel extract possesses a rich composition of polyphenol monomers, which potentially could regulate the growth and metabolism of intestinal probiotics.