Brain　computer　interface　(BCI)　is　a　technology　recording　brain　signals　and　translate　into　machine　language　to　drive　device　movement.　To　improve　the　convenience　and　practicability　of　BCI　systems,　it　is　necessary　to　reduce　the　number　of　channels　of　EEG　without　reducing　classification　accuracy.　In　this　paper,　a　channel　selection　method　was　proposed.　Combine　continuous　wavelet　transform　(CWT)　with　EEG　source　imaging　(ESI),　we　can　find　out　the　source　distribution　of　two　kinds　of　motor　imagery　(MI)　tasks　on　the　cortex.　Then　the　different　value　of　source　distribution　on　the　cortex　was　projected　to　scalp.　The　value　on　the　scalp　was　treated　as　a　criterion　for　channel　selection.　While　ESI　was　applied　for　locating　the　active　areas,　we　can　not　only　find　out　the　prior　channels　clearly,　but　also　figure　out　the　expected　areas　briefly.　The　satisfying　results　show　that　the　combination　of　CWT　and　ESI　is　a　potential　method　for　dealing　with　MI　tasks.