A system for testing a reflective display device includes a testing apparatus and a computer. The testing apparatus includes one or more light emitters, one or more light detectors, an analog-to-digital converter (ADC) module, and a microcontroller unit (MCU). The light emitters are for projecting light onto a reflective display device located on the testing apparatus. The light detectors are for sensing reflected light from the reflective display device, and generating electricity according to a luminance of the reflected light. The ADC module is for receiving the electrical signals from the light detectors, and producing a digital output according to voltages of the electrical signals. The MCU is configured for reading the digital output of the ADC module. The computer is for processing the digital output and displaying results after processing.