The　dielectric　response　function　with　relaxation　factor　was　applied　to　the　analysis　of　the　time-domain　dielectric　spectrum　of　the　recovery　voltage,　the　spectrum　of　the　time-differential　dielectric　line　was　decomposed,　the　sub-spectral　lines　containing　different　relaxation　information　were　obtained,　the　transformer　oil-paper　insulation　topological　structure　was　determined,　and　relaxation　parameters　were　found.　Further,　the　relaxation　parameters　and　self-insulation　status　of　more　than　30　different　models　of　oil-paper　insulation　transformers　were　analyzed.　The　relationship　between　relaxation　factors　and　deterioration　of　transformer　insulating　oil　and　aging　of　transformer　paper　was　excavated,　and　new　characteristic　quantities-the　average　relaxation　factor　of　insulating　oil　and　insulating　paper　averages　were　proposed　to　evaluate　insulation　status　of　insulating　oil　and　insulating　paper　in　oil-paper　transformers.　Finally,　the　actual　transformer　test　data　was　used　for　analysis　and　verification.　The　results　prove　that　the　two　new　feature　quantities　can　effectively　evaluate　the　insulation　status　of　the　insulating　oil　and　insulating　paper　in　the　transformer.　©　2019,　Harbin　University　of　Science　and　Technology　Publication.　All　right　reserved.