The invention relates to the technical field of medical products, in particular to a medical skin marker. The medical skin marker comprises marker body formed by a cap, a nib and a holder, the markerbody is internally provided with an inner core, and one end of the nib is inserted into the inner core filled with gentian violet ink. The gentian violet ink is at least prepared from gentian violet,potassium sorbate, 4-tert-butylcyclohexanol, white oil, L-arginine, cyclodextrin, alcohol with 2-6 carbon atoms and distilled water.