Return　voltage　measurement　(RVM)　is　a　non-destructive　detection　method　for　studying　power　transformer　oil-paper　insulation　aging　status.　In　this　paper,　a　lot　of　power　transformer　test　data　are　obtained　with　the　return　voltage　method;　the　improved　analytic　hierarchy　process　and　gray　correlation　method　is　proposed　and　used　to　comprehensively　evaluate　the　oil　paper　insulation　aging　status　of　power　transformer.　Firstly,　based　on　the　return　voltage　method,　the　characteristic　quantity　measured　with　the　return　voltage　method　and　the　characteristic　quantity　based　on　ED　equivalent　circuit　are　extracted　and　used　as　the　oil　paper　insulation　aging　evaluation　characteristic　quantities　of　power　transformer.　Secondly,　it　is　proposed　that　the　improved　analytic　hierarchy　process　method　is　used　to　allocate　the　weights　of　the　characteristic　quantities.　Considering　that　the　power　transformer　insulation　status　can　be　seen　as　a　typical　gray　system,　the　improved　analytical　hierarchy　process　(AHP)　-　grey　relation　diagnosis　algorithm　is　adopted　to　comprehensively　evaluate　the　oil　paper　insulation　aging　status　of　power　transformer;　Finally,　a　large　number　of　data　of　the　power　transformers　with　known　insulation　status　were　collected　to　establish　a　standard　state　vector　table,　and　actual　examples　were　used　to　verify　the　proposed　diagnosis　algorithm;　the　results　show　that　the　proposed　algorithm　can　fast　and　accurately　evaluate　the　insulation　condition　of　power　transformer,　which　provides　a　new　idea　and　method　for　the　evaluation　of　power　transformer　insulation　condition.　©,　2015,　Science　Press.　All　right　reserved.