Go/NoGo tasks are a useful behavioral model in the study of cognitive neurosciences. The present developmental study is aimed at establishing a developmental protocol of Go/NoGo visual-discrimination tasks to investigate more cognitive process. We used two rhesus monkeys to test our procedures. Our results suggested that the monkeys quickly learned Go/NoGo visual-discrimination tasks, and performed NoGo tasks better and easier than Go tasks. Using this visual-discrimination task, we can easily study related cognitive neurosciences.