Determination　of　the　configuration　and　size　of　fracture　process　zone　(FPZ)　at　dynamic　crack　tip　is　still　a　problem　unsolved　completely　at　present.　In　this　paper,　based　on　elastic　dynamic　theory　and　stress　functions,　a　method　for　evaluating　the　configuration　and　the　size　of　FPZ　is　proposed　and　the　feasibility　of　the　method　is　demonstrated.　The　configuration　and　size　of　the　FPZ　near　the　crack　tip　in　dependence　on　crack　propagation　velocity　are　determined　by　using　the　Von　Mises　and　Tresca　criteria,　respectively.　Numerical　results　show　that　FPZ　at　mode　II　and　mode　III　dynamic　crack　tip　is　distributed　symmetrically　with　respect　to　crack　plane　and　increases　with　the　crack　propagation　velocity.　FPZ　changes　more　rapidly　when　the　Rayleigh　wave　velocity　is　approached.　The　effects　of　Poisson＇s　ratio　on　FPZ　are　discussed.　Analysis　reveals　an　intricate　dependence　on　Poisson＇s　ratio　in　plane　strain　condition.