Using　group　theory　calculations　combined　with　the　force-constant　model　and　molecular-dynamics　simulations,　whether　the　deformed　modes　are　Raman　active　or　not　for　(10,10)　and　(10,0)　single-wall　carbon　nanotubes　under　hydrostatic　pressure　is　discussed.　With　increasing　pressure,　the　tube　symmetry　lowers　from　D-20h　to　D-2h　then　to　C-2h　point　group.　For　D-20h,　A(1g)　is　changed　to　A(g),　while　E-1g　and　E-2g　are　split:　E-1g　-＞　B-2g　+　B-3g　-＞　2(Bg)　and　E-2g　-＞　A(g)　+　B-1g　-＞　2A(g).　On　the　basis　of　the　correlation　between　D-20h,　D-2h,　and　C-2h　point　groups,　the　deformed　modes　should　be　still　Raman　active.　The　result　can　help　us　clarify　the　essence　of　the　experimental　observations.　(C)　2008　Elsevier　B.V.　All　rights　reserved.