A projector with a cyclic heat sink, comprising a housing (1), an exhaust fan (2), and a heat sink (3), the housing (1) being a hollow structure, the housing (1) being internally provided with an LED light source (5), a lens assembly (6), and a reflector (7), a lens (4) being fixedly mounted on the outer side of the housing (1), and the exhaust fan (2) and the heat sink (3) being attached to the housing (1) and positioned on the same side as the lens (4); the exhaust fan (2) is arranged between the heat sink (3) and the housing (1), one side of the housing (1) being provided with an air inlet (11), and the air inlet (11) being positioned at the rear end of the reflector (7); during operation, the exhaust fan (2) sucks air from the air inlet (11), which drives heat to the heat sink (3) after passing through the lens assembly (6), thereby dissipating heat. Cyclic heat dissipation is implemented by means of the arrangement of the air inlet (11) and the exhaust fan (2), enabling the heat inside the projector to be quickly dissipated into the air.