With the development of computer science and virtual reality technology, virtual world evolves along the way of computer game development, from arcade games, console system games, LAN games, Internet connectivity games, unstructured games, games with player generation of content, worlds with designer-provided objectives, games with social networks, and open virtual worlds [1]. Traditional server-client structure does not scale well at least in the following three aspects which are limited number of players in each server, single point of failure risk, and unbalanced computation resource. This survey investigates another alternative, peer-to-peer (P2P) virtual world software infrastructure, to address these traditional architectural issues. © 2012 IEEE.