Abstract: Online auction is so necessary today because millions of dollars change daily through this market .this allows fraud to occur by malicious users , so trust relationships is important ,this paper investigate new trust model for C2C auction market, proposed a framework depend on seller rating , analysis for Increase Price and using social network to ask about participants than store all in data base than using on swarm intelligence such as Ant colony optimization and Particle swarm Optimization for more high performance.

Keywords: Trust Model, Online Auctions, Rating, Social Network, Ant Colony Optimization.