The present invention, pertaining to the field of plant cultivation, provides a plant growth control system and method. The system (100) comprises: an information collector (110), a processor (120) connected to the information collector (110), and a controllable light source (130)； wherein the information collector (110) is configured to acquire growth information of a plant, the growth information comprising at least one of branch and leaf distribution information of the plant and flower distribution information of the plant； and the processor (120) is configured to determine, according to the growth information, a target irradiation position of the controllable light source (130) in the plant, and to control the controllable light source (130) to irradiate the target irradiation position in the plant.
