Transformer　oil　can　produce　impurities　such　as　water,　dissolved　gases,　or　other　particles　due　to　aging,　which　can　seriously　reduce　the　insulation　performance　of　power　transformers.　The　internal　characteristics　of　transformer　oil　will　be　changed　when　it　is　filtered　by　films.　In　order　to　explore　the　characteristics,　this　paper　considers　the　effects　of　different　kinds　of　oil　filtering　films　and　oil　filtering　times　on　the　water　content　and　voltage　breakdown　characteristics　of　transformer　oil.　The　results　show　that　the　times　of　oil　filtration　have　a　certain　influence　on　the　water　removal　of　transformer　oil.　The　water　removal　effect　is　not　obvious　when　the　transformer　oil　is　filtered　once,　and　it　is　found　that　the　effect　is　better　when　the　transformer　oil　is　filtered　three　times.　Different　films　have　different　filtering　effects　on　transformer　oil.　It　is　concluded　that　the　modification　of　organic　films　with　SiO2　particles　gives　excellent　results　in　terms　of　performance　and　is　effective　for　transformer　oil　filtration.　©　2023　IEEE.