The invention discloses a down lamp adjustable in irradiation angle, and the irradiation angle can be changed. The down lamp comprises a bracket and an outer surface ring arranged on the bracket. A rotating inner barrel is movably arranged on the bracket. A circumferential rotating gear is arranged on the back surface of the rotating inner barrel. A rotating shaft is arranged in the center of the circumferential rotating gear and movably arranged on the bracket. A circumferential adjusting mechanism is arranged on the bracket. A radiator is arranged in the rotating inner barrel. One side of the radiator is movably hinged to the rotating inner barrel, and the other side of the radiator is provided with a circular-arc-shaped inclination angle adjusting rack. An inclination angle adjusting mechanism is arranged between the rotating inner barrel and the inclination angle adjusting rack. An irradiation unit is installed in the radiator. The down lamp adjustable in irradiation angle is very wide in purpose and can be widely used in all kinds of interior decorations.