We　investigate　the　entanglement　dynamics　of　an　entangled　atom　pair　via　Wootters＇　concurrence.　Only　one　atom　of　the　pair　interacts　with　a　two-mode　cavity　field　via　a　Raman　interaction.　The　number　simulation　shows　that　the　entanglement　of　the　atom　pair　will　display　sudden　death　and　revival　phenomena　when　the　cavity　photon　numbers　and　the　two-mode　atom-cavity　coupling　strengths　are　changed.　Due　to　the　two-mode　field　effect,　the　entanglement　sudden　death　phenomenon　will　disappear　more　easily　by　enlarging　the　different　cavity　mode-atom　coupling　ratio.　The　oscillation　rate　of　the　concurrence　is　enlarged　by　increasing　the　mean　photon　number　of　the　cavity　field.