As　entities　in　distributed　environments　lack　sufficient　global　information,　it　is　difficult　to　evaluate　trust　accurately.　By　considering　characteristics　of　resources　in　distributed　environments　such　as　openness,　dynamicity　and　uncertainty,　we　proposed　a　new　dynamic　trust　evaluation　model　in　this　paper.　The　model　describes　factors　that　can　affect　trust　evaluation　based　on　a　multi-dimensional　view　that　include　static　attributes　of　entities,　time-based　behavior　speculation,　context　awareness　and　communication　conditions.　Genetic　algorithm　(GA)　is　then　introduced　to　do　trust　computation　in　the　proposed　model,　which　is　important　due　to　the　lack　of　mathematical　tools　in　traditional　trust　models　for　multi-dimensional　data　processing.　Simulation　results　show　that　our　proposed　model　is　better　compared　to　other　trust　evaluation　models.　©2010　IEEE.