Web　service　choreography　specifies　the　interaction　among　multiple　participant,　aiming　to　achieve　common　business　goals.　An　issue　is　to　check　for　the　conformance　of　the　implementation　with　reference　to　the　choreography　specification.　To　achieve　that,　we　seek　to　develop　software　tools　and　a　methodology　to　enable　conformance　testing　of　choreography.　In　this　paper　we　present　our　first　step　in　that　direction.　Particularly,　we　reduce　choreography　scenario　in　order　to　obtain　effective　testing　scenarios,　which　will　greatly　decrease　the　cost　of　testing.　Concretely,　based　on　XML　Schema　type　definition　of　a　choreography　scenario,　we　partition　XML　Schema　type　into　subtypes,　which　will　be　transformed　into　the　input　model　of　combinatorial　tool　Cascade　for　generating　a　set　of　combinations　of　variable　values.　The　output　of　Cascade　will　be　transformed　to　generate　reduced　scenarios　for　testing.　Moreover,　a　purchase　order　choreography　example　is　presented　to　demonstrate　the　reduction　process　of　choreography　scenarios,　and　a　tool　has　been　developed　for　supporting　automatic　implementation　of　the　testing　scenarios　reduction.