In recent years, online auction systems such as eBay have been more and more popular. The client-server architecture is usually adopted for the basic architecture of online auction systems. However, the client/server architecture usually causes the problems of bandwidth bottleneck and insufficient storage spaces. Therefore, we propose to replace the client/server architecture of traditional online auction systems to P2P architecture for distributing the loading and storage requirement to peers by sellers and buyers. Also, OpenID is exploited to be integrated into our system so that users do not have to remember multiple accounts and passwords. In this paper, the design of an OpenID integrated P2P auction system is proposed. Also, the comparison of our system design and other related P2P auction systems will be discussed.