Use of Mirabilis jalapa L. extracts and skin external preparations comprising the same. Specifically the use of Mirabilis jalapa L. extract for manufacturing an agent selected from the group consisting of an antioxidant, a melanin synthesis inhibitor, an elastic fiber hydrolysis inhibitor, and an anti-skin aging protein expression up-regulation agent. The Mirabilis jalapa L. extract, especially the Mirabilis jalapa L. flower extract, has the effects of scavenging free radical activity, inhibiting tyrosinase activity, inhibiting elastase activity and up-regulating the anti-aging protein expression in human fibroblasts, which can regulate the production of collagen in the dermis and has anti-aging effect.