The bacteriorhodopsin-based electrochemical junction photocell was employed to implement an artificial cortex simple cell receptive field. A stationary flashing stimulus was used to indicate characteristics of the photoreceptor. The results showed that its map was characterized as the excitatory and inhibitory areas. Like the simple cell receptive field in the cat striate cortex, the artificial receptive field exhibited orientation- and length-selective characteristics which are useful for visual information processing.