Melasma is an acquired hyperpigmentation skin disease, mostly symmetrically distributed on both cheeks, shaped like a butterfly, also known as “butterfly spot”. Melasma not only affects the appearance, but also brings negative impact to patients’ mental and psychological aspects and aggravates the progress of the disease. The etiology and pathogenesis of melasma are not fully understood. It is easy to diagnose melasma and there are many treatment methods, such as laser and intense pulsed light treatment, oral and topical medications, etc. However, all methods have different degrees of adverse reactions, and different patients have different degrees of requirements for treatment methods due to the different severity of the disease and the needs of their working life. In August 2012, our hospital started to use L-vitamin C ultrasonic introduction combined with external application of nicotinamide gel to treat melasma and achieved more satisfactory results. Ultrasound has the function of destroying the inner membrane of pigment cells, preventing or reducing pigment formation, accelerating pigment excretion, and also promoting the role of drug penetration into the skin. Its mechanical, chemical and physical effects can improve blood circulation, promote metabolism, strengthen enzyme activity and cell membrane permeability, facilitate material exchange and prevent cells from absorbing nutrients, and improve the regenerative ability and repair function of skin tissues. L-vitamin C has a small molecular weight and is the only form of vitamin C that can be directly absorbed by human skin. Vitamin C affects the activity of certain substances (mainly tyrosinase) that participate in the biochemical reactions of melanogenesis. Vitamin C and the deoxygenated vitamin C produced by its oxidation can reduce darker oxidized pigments to lighter reduced pigments and dopaquinone to dopa, thus inhibiting melanin formation. The human body cannot synthesize and store vitamin C on its own, so it must be obtained from outside sources. Nicotinamide is an important component of coenzyme I and II, which acts as a hydrogen-delivery agent in the biological oxidation process, promoting biological oxidation and tissue metabolism, and it inhibits the transport of melanosomes from melanocytes to surrounding keratin-forming cells. Niacinamide is the most stable water-soluble vitamin in light and air and has the least skin irritation of all vitamins. Topical nicotinamide gel has been reported in the literature to have topical anti-inflammatory, skin stratum corneum barrier improvement and emolliency, skin pigmentation reduction, improvement of facial skin aging manifestations, and prevention of photoimmunosuppression and photocarcinogenesis. Our hospital has treated tens of thousands of people with melasma by using levovitamin C ultrasonic introduction combined with topical nicotinamide gel, which has proven to be effective in treating melasma with no significant adverse reactions, and is worthy of clinical promotion for the benefit of melasma patients.