Illumination control system and control method

The invention provides an illumination control system. The illumination control system includes an illuminance monitoring module, a control module and an execution unit; the illuminance monitoring module measures illuminance; the execution unit has various kinds of working states; the control module computes input signals and sends control commands to the execution unit to make the execution unit switched between the various kinds of working states; the control module comprises a storage module which stores execution threshold values and switching-off threshold values, a comparator which compares inputted illuminance data with the threshold values, an execution arithmetic unit which generates control commands according to the computation results of the comparator and outputs the control commands, a switching-off threshold value calculation module which reads current illuminance data according to the control commands of the execution arithmetic unit, and performs computation and generates a new switching-off threshold value, and writes the new switching-off threshold value into the storage module. The invention also provides a control method of the illumination control system. According to the illumination control system and control method of the invention, the actual illuminance of a switched-on lamp is measured, and then, a switching-off threshold value can be calculated, and therefore, the switching-off threshold value can change with environmental factors, and precise control can be realized.