The utility model provides an illumination and carbon dioxide concentration control system of a greenhouse. The control system comprises a control module, an LED illuminating lamp, a light homogenizing plate, a timer, a ventilator, a dry ice release module, a motor driving module, a photosensitive sensor, a power module, a carbon dioxide concentration detector, a display screen, an illumination driving module and an alarm device. The timer, the photosensitive sensor, the motor driving module, the carbon dioxide concentration detector, the display screen, the alarm device and the illumination driving module are electrically connected with the control module; the output end of the lighting driving module is electrically connected with the LED lighting lamp; the greenhouse is divided into a plurality of areas to be controlled through the illumination driving modules, the light supplementing time and the illumination intensity of each area can be completed through setting, the carbon dioxide concentration detection module is further arranged, and the concentration of carbon dioxide in the greenhouse is controlled through the ventilation fan and the dry ice release module.