Plant factory as well as working method thereof

The invention relates to a plant factory as well as a working method thereof. The plant factory comprises a support, a plant culture base is arranged at the lower part of the support, a light source mounting frame capable of moving up and down is arranged at the upper part of the support, multiple LED lamps are arranged below the light source mounting frame, a device for adjusting the irradiationangle of each LED lamp is arranged on the light source mounting frame, a lamp holder fixing mechanism capable of moving up and down is arranged below the light source mounting frame, a focusing zoom cylinder sleeved outside the LED lamps is arranged on the lamp holder fixing mechanism, and spot size and illumination intensity of the LED lamps are changed through moving up and down. The working method of the plant factory comprises the steps as follows: when plants are young, the LED lamps and focusing zoom cylinder are reduced, until ordinary non-focusing illumination is used, the irradiationangle of LED lamps is adju