At the end of last century, scientists began to explore cortical circuit of cognition and memory with split-brain surgery. Later, they tried to treat epilepsy with split-brain surgery and achieved certain results. Since then, scientists have tried to understand the functional differences between the left and right hemispheres and the effects of the split brain on behavioral cognition by working with different animals as well as patients with the split brain. The ongoing study of split-brain provides theoretical explanations for clinical brain imaging findings and continues to help us understand the mechanisms of cognition and memory. Split-brain patients are always valuable samples for scientists to study inter-hemispheric structural and functional connectivity, differences in the two hemispheres, integration of sensory, motor, and spatial information, and general behaviour. The following information summarizes split-brain related concepts and includes methods and experiments to find the results for the studies mentioned above to help readers understand how these achievements were reached.