Partial　discharge　(PD)　seriously　affects　the　safe　operation　of　power　transformer.　Studying　the　influence　of　PD　in　internal　bubble　of　oil　paper　insulation　and　understanding　the　insulation　failure　mechanism　can　provide　guidance　for　engineering　practice.　In　this　paper,　the　induction　mechanism　of　PD　on　insulation　failure　is　obtained　by　analyzing　the　short-time　breakdown　characteristics　of　oil　paper　insulation　with　different　bubble　parameters.　Through　the　comparative　analysis　of　bubble　area　and　PD　parameters,　a　positive　feedback　model　for　the　insulation　degradation　is　obtained,　representing　that　bubble　defects　will　deteriorate　rapidly　in　exponential　form　under　the　effect　of　PD.　Finally,　with　the　help　of　electron　microscope　and　energy　spectrum　analysis,　the　deterioration　process　of　insulating　paper　is　divided　into　four　stages,　obtaining　the　micro　deterioration　and　failure　mechanism　of　insulating　paper.　©　2021　IEEE.