The Civil Code separates rural land ownership, contract right and management right, forming a new pattern of "three rights separation", which is another important institutional innovation in rural land reform after the household contract responsibility system. However, in the process of the implementation of the separation of the three rights of agricultural land, the rights of ownership, contract right and management right are not clear enough, and the boundary of rights is fuzzy, which makes the implementation of the separation of the three rights of agricultural land face many obstacles. This paper discusses the evolution process, connotation, nature and boundary of the policy of separating the three rights of agricultural land, aiming at clarifying the right boundary of ownership, contract right and management right of agricultural land, implementing the "separation of the three rights" and promoting the development of rural industries.