Abstract: The present invention provides a plant growth lamp, which includes a lamp body (1), and a driving power supply, an LED luminary (2) and a heat dissipation part (3) provided inside the lamp body (1). The LED luminary (2) comprises a substrate (4) and a plurality of LEDs provided on the substrate (4). The LED luminary (2) is regulated and controlled by a spectrum controller to generate various regular pulsed periodic spectral light signals, and the LEDs are connected with the heat dissipation part (3) via the substrate (4). The growth rate of plants can be greatly improved; the heat dissipation performance of the plant growth lamp is effectively improved and the service life of the plant growth lamp is prolonged, by the light irradiation of the lamp.