Ultra-high　harmonics　sources　such　as　photovoltaic　inverters,　charging　devices　of　electric　vehicles,　lighting　equipment　are　connected　to　the　power　grid　through　transformers,　which　makes　it　possible　for　ultra-high　harmonic　to　flow　into　the　power　grid　and　brings　power　quality　problems　to　the　power　grid.　The　influence　of　transformer　on　ultra-high　harmonics　transmission　has　become　a　research　hotspot　in　academia.　Considering　the　distributed　capacitance　parameters　of　transformer,　a　high　frequency　model　of　transformer　is　established　and　its　ultra-high　harmonics　transfer　characteristic　function　is　derived.　By　comparing　the　model　simulation　results　with　the　transformer　ultra-high　harmonics　transfer　function　deduced　by　theory,　it　is　found　that　the　distributed　capacitance　has　an　effect　on　the　ultra-high　harmonics　transfer　characteristics　of　transformer,　which　will　provide　a　direction　for　analyzing　and　solving　the　ultra-high　harmonics　problems　of　power　grid.　©　2020　IEEE.