Disclosed is a planting cabinet comprising: a fill light, a controller, a sunrise/sunset time acquisition device, and a clock device. The clock device is connected to the controller. The controller is used for controlling the fill light to start filling light when the actual time of the clock device reaches a sunrise time acquired by the sunrise/sunset time acquisition device and controlling the fill light to stop filling light when the actual time of the clock device reaches a sunset time acquired by the sunrise/sunset time acquisition device. Hence, lighting acquired by a plant in the planting cabinet can satisfy natural rhythm of sunrise and sunset times, thus facilitating the growth of the plant. Also disclosed is a lighting time adjusting method comprising: acquiring the sunrise time and sunset time of the geographical location at where a plant is located and the real-time time; determining whether the real-time time reaches the sunrise time; if yes, then filling light for the plant; determining whether the real-time time reaches the sunset time; and if yes, then stop filling light for the plant.