Densely deploying transmission nodes, reducing the radius of the cell, and obtaining greater cell division gain are the key means of 5G mobile communication system to achieve the goal of capacity improvement. This paper firstly introduces the meaning, typical coverage and challenges of 5G ultra dense network; secondly, analyzes the 5G virtual network architecture; finally, introduces the user centric virtualization technology of 5G mobile communication system, focusing on the advantages of residential virtualization and terminal virtualization technology in solving mobility and interference problems.