The invention relates to a nursery greenhouse which comprises a supplementary lighting lamp, a humidifier, more than one temperature sensor, more than one humidity sensor, more than one illumination intensity sensor and a PLC (programmable logic controller). The supplementary lighting lamp and the humidifier are used for regulating internal climate of the greenhouse. The temperature sensors, the humidity sensors and the illumination intensity sensors are used for measuring internal climate parameters of the greenhouse. The PLC acquires values of the temperature sensors, the humidity sensors and the illumination intensity sensors circularly, controls the humidifier to work according to the values of the humidity sensors, and controls the supplementary lighting lamp to be switched on according to the values of the illumination intensity sensors. The invention further discloses an internal climate regulating method of the nursery greenhouse. By the nursery greenhouse and the internal climate maintaining method thereof, clean energy is fully utilized, automatic control is realized, a local climate environment beneficial to growth of plants grown inside the greenhouse is created, energy is saved, and yield is increased.