Turbulence　with　a　relatively　larger　vortex　is　obtained　in　drag-reducing　surfactant　solution,　which　provides　an　excellent　condition　for　the　application　of　small　scale　grooves.　In　this　work,　the　coupling　drag　reduction　performance　of　surfactant　solution　and　grooves　was　experimentally　investigated　to　explore　the　complementary　possibility　between　their　drag　reduction　mechanisms.　The　cationic　surfactant　cetyltrimethyl　ammonium　chloride　(CTAC)　mixed　with　the　counterion　salt　sodium　salicylate　(NaSal)　was　experimented　in　smooth　or　grooved　channel,　respectively,　at　the　mass　concentrations　of　50-150　ppm.　It　was　found　that　the　surfactant　solutions　gave　more　effective　drag　reduction　in　the　grooved　channel　by　the　interaction　between　the　＂restriction　effect＂　and　＂peak　effect＂　of　grooves.　Moreover,　the　critical　temperature　and　critical　Reynolds　number　of　the　surfactant　solution　were　smaller　in　the　grooved　channel,　and　the　friction　factor　in　the　grooved　channel　increased　much　more　rapidly　than　that　in　the　smooth　channel　when　Re　is　larger　than　a　critical　value.