Event-Related Potential (ERP) is an alternative method of noninvasive, electrophysiological measurement techniques. It can provide precise millisecond data of sensory and cognitive processes concerning an event or information from a stimulus . ERP method also ideal for studying perception and attention . Visual signals are transmitted from cone cells and rod cells in the retina of the eye to the primary visual cortex  . People with red-green color vision deficiency have difficulty seeing numerical information hidden in the Ishihara plate test . In previous research , the experiment also used the Ishihara plate test as a visual stimulus, but the investigation was only conducted for normal vision people. Regarding this matter, we aimed to investigate the response of EEG signals between normal and partial color-blind people by using the ERP method, especially when they are given visual stimuli composed of images from the Ishihara book test. ERP investigation is essential in this study because it shows how information is processed by our brain over time, starting from the early sensory process to higher cognitive function stages.