Various　plant　oil　pitchs　(cottonseed　pitch,　bean　oil　pitch,　and　mixed　plant　oil　pitch)　were　used　to　prepare　the　plant　oil　pitch　binders　for　casting.　They　were　treated　by　polyester　waste　and　processed　by　several　technics　such　as　esterifying.　In　the　mean　time,　FTIR　and　TG　were　adopted　to　learn　the　structure,　property,　and　sclerous　mechanism　of　the　binders.　From　the　comparison　with　synthetic　fat　binder,　the　authors　can　see　that　the　treated　binders　have　similar　components.　They　also　have　many　excellent　properties　such　as　higher　dry　tensile　strength　and　slower　deflation　velocity,　which　equal　to　or　even　exceed　the　properties　of　synthetic　fat　binder.　Therefore,　the　treated　binders,　which　were　cheaper,　can　be　used　to　make　class　I　mold　and　core　binders.