The invention relates to a radiator structure of a semiconductor lighting fixture, aiming at, under the condition of not changing the volume of the semiconductor fixture, effectively adjusting radiating power distribution of radiating elements in the fixture, forming rational temperature gradient of gas in the fixture and further acting in concert with a gas flowing heat transfer passage formed by the shell structure of the fixture to achieve the objective of raising the flow rate of the heat transfer gas in the fixture, namely improving heat radiation in the fixture. The radiator structure comprises a fixture shell and a semiconductor light source heating device arranged in the fixture shell; wherein, at least one side of the semiconductor light source heating device is provided with the radiating element thermally communicated therewith; the radiating element is positioned in the fixture shell; a cold air inlet is correspondingly arranged on the lower surface of the fixture shell and a hot air outlet is correspondingly arranged on the upper surface thereof. The radiator structure can effectively improve the radiating effect of the semiconductor light source heating device in the fixture.