Carbon　nanotubes　were　prepared　on　silicon　wafers　deposited　with　NiFe　catalyst　films　and　Ta　buffer　films　by　plasma-enhanced　hot　filament　chemical　vapor　deposition,　and　growth　of　the　carbon　nanotubes　under　different　pressure　were　investigated　by　scanning　electron　microscopy.　It　is　found　that　the　average　length　of　the　carbon　nanotubes　grown　at　the　pressure　of　15　Torr　is　larger　than　that　at　the　pressure　of　30　Torr.　But,　it　is　difficult　to　grow　the　carbon　nanotubes　when　the　pressure　is　5　Torr.　These　indicate　that　the　pressure　greatly　influences　on　the　growth　of　carbon　nanotubes.　Combined　with　theories　related　to　thermodynamics　of　alloy　and　glow　discharge,　it　is　analyzed　and　discussed　that　the　pressure　affects　the　growth　of　the　carbon　nanotubes.　(C)　2004　Elsevier　B.V.　All　rights　reserved.