Running　GUI　(Graphic　User　Interface)　test　cases　is　a　time-consuming　task.　In　order　to　improve　test　effectiveness,　it　is　necessary　to　eliminate　redundant　test　cases　from　test　suite.　This　paper　presents　an　approach　for　reducing　test　suite　based　on　test　cases＇　running　information,　which　includes　path　information　of　event　handler　function　and　invoked　method　sequence　of　running　threads.　In　this　approach,　a　relationship　between　two　test　cases　is　defined,　and　some　test　cases　are　regarded　to　be　redundant　according　to　the　relationship　and　the　running　information.　Based　on　the　idea,　we　implement　a　prototype　for　Windows　GUI　applications.　Initial　experiment　shows　that　the　test　suite　produced　by　our　approach　has　larger　size　and　higher　fault　detection　effectiveness　than　that　produced　by　call　stack　coverage　approach[1],　and　running　reduced　test　suite　save　about　19%　time　compared　to　the　original.