This paper surveys the techniques and benefits of MIMO introduced in Cognitive Radio Network. Cognitive Radio (CR) is one of the upcoming technologies for future wireless network. With developments in wireless technologies increasing at a tremendous pace, the frequency spectrum has become a scarce resource. The cognition in spectrum sensing and sharing becomes the key idea of this technology leading to a judicious use of available spectral resources. Hence this technology is touted to dominate the future communication network. Cognitive Radio equips wireless users with the capability to optimally adapt their operating parameters according to the interactions with the surrounding radio environment and utilize the spectrum more efficiently in an opportunistic fashion without interfering with the primary users.