This study examined the physiological activities and functional components of the extracts of the stem and fruit from Opuntia monacantha Haw. (Cactaceae) for the development of future functional food. The total polyphenol and flavonoid contents of the extract ranged from 8.00 to 9.46 mg GAE/g FW and 0.18 to 0.27 mg CE/g FW, respectively. In addition, the main carotenoids of the stem extract were β-carotene (299.66 μg/g DW), lutein (152.59 μg/g DW), and α-carotene (87.69 μg/g DW), and that of the fruit extract was β-carotene (26.35 μg/g DW).The chlorophyll a content of the stem and fruit extract was 408.81 and 22.64 μg/g, respectively, and the chlorophyll b content of the stem and fruit extract was 156.97 and 9.98 μg/g, respectively. The inhibitory activities of ɑ-glucosidase, acetylcholinesterase, elastase and tyrosinase suggested that the Opuntia monacantha Haw. extract can be used as a new source of natural functional materials.