We　theoretically　investigate　dressed-four-wave　mixing　(dressed-FWM)　spectroscopy　of　rubidium　atoms　in　a　micrometric　thin　vapour.　It　is　found　that　Dike-narrowing　type　Autler-Townes　(AT)　spectroscopy　with　high　resolution　can　be　achieved　in　a　reverse　Y-type　four-level　atomic　system　due　to　the　phase-conjugated　configuration　of　laser　beams　and　the　transient　effects　of　atom-wall　collision　in　the　thin　vapour.　We　also　show　that　controllable　suppression　and　enhancement　of　the　dressed-FWM　signal　due　to　the　evolution　of　atomic　coherence　can　be　obtained　by　selecting　different　coupling　field　intensities　at　the　proper　detuning　of　the　probe　and　the　coupling　fields.　This　control　of　FWM　processes　can　be　interpreted　by　dressed　state　analysis　and　probably　used　in　the　design　of　optical　switch　and　the　enhancement　of　FWM　processes　for　frequency　conversion.