The present invention provides a plant growth lamp module and a plant growth lamp using this module. A plurality of the plant growth lamp modules can be connected. The module comprises a casing; a power supply in the casing; a male socket and a female socket disposed on two inner sides of the casing respectively and electrically connected to the power supply; and a lighting unit disposed in the casing and electrically connected to the power supply to emit light after energizing, which is transmitted outwards via a hole. The plant growth lamp in the present invention may have various adjustments to meet growth needs of various kinds of plants. Further, the plant growth lamp in the present invention enables plants to carry out photosynthesis even in an environment without sunlight and stimulate healthy growth of plants.