The embodiment of the invention provides a plant cultivating device, and relates to the technical field of intelligent cultivating. The plant cultivating device comprises a main machine and a cultivating box which are mutually communicated, wherein the main machine comprises a nutrient solution storage bottle, a water pump, a refrigerating system and a controller; the cultivating box comprises a lamp tube, a plurality of partition plates with adjustable intervals, a temperature sensor and a plurality of water pipes. The controller controls the water pump to provide water or a nutrient solution for the multiple water pipes, controls the lamp tube to be started or closed, and controls working time of the refrigerating system according to the cultivating-box temperature detected the temperature sensor. The partition plates are supported through a plurality of supporting stripes respectively, it is achieved that the intervals of the partition plates are adjustable, and the plant cultivating device can be suitable for a plurality of plants; the main machine and the cultivating box are modularized, one main machine can be connected with multiple cultivating boxes, assembling is convenient, and the cost is low; space and illumination of a balcony can be well used, and the plant cultivating device is capable of saving energy, environmentally friendly and suitable for ordinary families.