In　order　to　integrate　different　kinds　of　information　in　the　water　affairs　field,　this　paper　proposes　an　improved　comprehensive　semantic　similarity　algorithm　and　applies　it　to　the　construction　of　water　affairs　ontology.　In　this　article,　the　algorithm　is　to　give　the　concept　instance　similarity　algorithm　and　concept　definition　similarity　algorithm　appropriate　weight.　First,　we　apply　the　three　algorithms　to　the　concept　of　the　local　ontology　of　smart　water,　and　then　calculate　the　similarity　between　the　concepts　to　judge　the　similarity　between　the　concepts　to　merge　the　smart　water　data,　and　finally　compare　the　similarities　of　the　three　algorithms　Degree　value　and　calculation　and　comparison　of　three　similarity　variance　values　prove　the　effectiveness　of　the　method.　It　can　be　seen　from　the　experimental　results　that　the　variance　of　the　comprehensive　similarity　calculation　method　is　smaller　than　that　of　the　other　two　methods,　and　it　is　easier　to　determine　the　similarity　between　two　concepts.　©　2020　Published　under　licence　by　IOP　Publishing　Ltd.