As　rural　building　boundaries　are　widely　used　in　GIS　for　building　density　calculation,　landscape　fragmentation　and　suitability　evaluation,　the　correctness　of　boundary　determination　has　an　important　impact　on　the　results　of　these　calculations　and　evaluations.　For　this　reason,　this　paper　proposes　a　rural　building　boundary　search　algorithm　called　ABTA.　The　ABTA　method　is　based　on　a　row　and　column　search　and　uses　only　one　parameter　step　to　control　the　＇smoothness＇of　the　final　solution.　The　algorithm　generates　convex　hulls　representing　the　area　occupied　by　the　given　buildings.　It　is　implemented　as　a　VBA　package　and　is　embedded　in　AutoCAD.　The　results　show　that　the　proposed　algorithm　can　deal　with　arbitrary　polyline　sets　and　can　accurately　determine　building　boundaries.　©　2021　ACM.