Analyzing　the　equivalent　circuit　of　oil　paper　insulation　is　one　of　the　effective　ways　to　diagnose　aging　of　transformer　insulation.　It　is　difficult　to　accurately　identify　the　parameters　in　current　research.　We　abandon　the　method　of　using　the　recovery　voltage　characteristics　to　identify　the　parameters　of　oil　paper　insulation,　and　present　a　new　method　to　identify　circuit　model　and　parameter.　Adopting　the　voltage　curve　which　contains　rich　dielectric　relaxation　response　information　and　the　differential　spectrum　response　voltage　of　dielectric　relaxation　response　information　which　contains　dielectric　relaxation　response　information,　we　analyze　the　relationship　between　the　relaxation　parameters　and　the　parameters　of　the　equivalent　circuit.　The　new　method　can　determine　the　equivalent　circuit　topology,　and　avoid　complex　computation　equations.　Meanwhile,　it　can　solve　the　linear　parameters　of　atypical　free　relaxation,　and　the　results　show　the　method　is　feasible　and　accurate.　Finally,　the　relationship　between　equivalent　circuit　parameters　of　transformer　insulation　and　aging　status　is　studied.　The　results　indicate　that　the　recovery　voltage　can　be　decomposed　to　five　sub-lines,　and　the　line　shape　factors　close　to　0.5　when　the　insulation　performance　is　good,　the　number　of　sub-lines　and　line　shape　factors　increases　with　ageing.　Therefore,　the　number　of　sub-lines　and　linear　parameters　can　accurately　reflect　the　state　of　oilpaper　insulation　aging.　©　2017,　High　Voltage　Engineering　Editorial　Department　of　CEPRI.　All　right　reserved.