Disclosed is a plant growth lamp, which comprises a lamp body (1), a drive power supply provided in the lamp body (1), an LED light-emitting body (2), and a heat dissipation portion (3), wherein the LED light-emitting body (2) comprises a substrate (4) and a plurality of LED lamp beads are provided on the substrate (4)； the LED light-emitting body (2) is regulated by a spectrum controller to generate various regular pulse-type periodic spectrum light signals； and the LED lamp beads are connected to the heat dissipation portion (3) via the substrate (4). By means of the light irradiation of such a lamp, the growing speed of a plant can be greatly improved, and the heat dissipation of the plant growth lamp is effectively improved to prolong the service life of the plant growth lamp.
