Based　on　the　extended　Debye　model,　the　interface　polarization　branch　is　introduced　to　make　the　oil-paper　insulation　mixed　polarization　equivalent　model　more　suitable　for　the　actual　polarization　process.　The　mixed　polarization　equivalent　model　parameter　identification　method　using　frequency　domain　dielectric　spectrum　is　studied.　Firstly,　the　relationship　between　the　frequency　domain　spectrum　and　the　circuit　parameters　is　derived　based　on　the　mixed　polarization　equivalent　circuit.　Secondly,　the　objective　function　of　the　equations　for　solving　the　multivariate　parameters　is　established,　and　the　artificial　intelligence　algorithm　is　used　to　solve　the　parameters.　Finally,　the　method　is　used　to　verify　the　identification　of　the　method.　Feasibility　and　accuracy　of　mixed　polarization　equivalent　model　parameters.　The　calculation　results　show　that　the　mixed　equivalent　model　considering　interface　polarization　can　more　accurately　reflect　the　relaxation　process　of　oil-paper　insulation.　Compared　with　the　time　domain　dielectric　spectrum　parameter　identification　method,　the　identification　method　based　on　frequency　domain　dielectric　spectrum　has　the　advantages　of　simple　solving　process　and　accurate　and　reliable　parameter　calculation　results.　©　Published　under　licence　by　IOP　Publishing　Ltd.