a light measurement system measures light characteristics of a plurality of light sources and includes a processing unit , a plurality of capturing modules , a plurality of signal conversion units , and a demultiplexing unit . the processing unit generates a control signal for controlling the capturing modules to capture the light characteristics of the light sources . after capturing the light characteristics , the capturing modules output captured frequency - related data corresponding to the light characteristics respectively . then , the capture frequency - related data are converted into capture bit codes by the signal conversion units respectively . under the control of the processing unit , the demultiplexing unit selectively sends the capture bit code of each of the signal conversion units to the processing unit . accordingly , the light measurement system measures the light sources synchronously and allows the demultiplexing unit to send the capture bit code of any one of the light sources to the processing unit .