the　theory　of　social　network　and　the　harvest　of　trust　models　are　researched.　The　trust　model　of　E-Commerce　based　on　social　network　is　built,　and　the　recommendation　path　building　algorithm　is　given.　After　considering　the　weight　of　the　relationship　between　Internet　members,　trust　degree　of　recommendation　nodes,　trust　value　attenuation　with　time　and　trade　risk　level　about　money,　the　simulation　experiment　on　those　factors　is　performed.　The　result　indicates　that　the　trust　network　mechanism　based　on　social　network　is　effective　for　restricting　trust　attack　behavior　in　Internet　and　it　provides　trusty　environments　for　trades　of　E-Commerce　between　Internet　members.　©　2008　IEEE.