The invention discloses a cactus mask for treating acne and a preparation method. The cactus mask is prepared from, by weight, terbinafine hydrochloride, cacti, blueberries, radix glycyrrhizae preparata, carmine radish, nagens groundsel, hemigraphis procumbens (Lour.) Merr., holboellia latifolia wall, all-grass of Taiwan lettuce, roots of angled bittersweet, prawn shells, chamomile essential oil, sandalwood essential oil, pearls, gypsum, para aminobenzoic acid, carboxymethylcellulose, sorbitol and polyvinyl alcohol. The preparation method comprises the steps of material preparation, juicing, extraction of effective ingredients of Chinese herbal materials and preparation of the mask. According to the mask, all the herbal materials are matched properly, and the mask is mild and effective and can effectively treat acne, remove blackheads, whiten and nourish skin, lighten color spots and scars, resist oxidation, promote skin metabolism, enhance blood vessels and skin elasticity, boost blood circulation, improve skin smoothness, inhibit inflammations and allergies and increase skin resistance.