The present invention relates to a composition for treating or preventing neurodegenerative brain diseases comprising a black bean extract, and more particularly, to a composition for treating or preventing neurodegenerative brain diseases comprising a black bean extract or a fraction thereof, which comprises 15-25 wt % of delphinidin-3-glucoside, 65-80 wt % of cyanidin-3-glucoside and 5-10 wt % of petunidin-3-glucoside, a functional food composition for enhancing brain or cognitive function comprising the black bean extract or a fraction thereof, and a method for preparing the composition.
