This invention provides a quick detaching device for handgun tactical light which includes a tactical light base, two locking members correspondingly disposed on two sides of a top end of the tactical light base, sliding members and a pressing mechanism; a sliding slot is correspondingly mounted in a middle part of each of the sliding members; the sliding members are respectively mounted in the sliding slots; a through slot which passes through the tactical light base is provided in the tactical light base; a stopping plate is provided in a middle part of the through slot; the pressing mechanism is mounted in the through slot and corresponds to the stopping plate. This invention can quickly mount and detach the tactical light without the help of tools and great effort, and is convenient to use.