In　the　DC　GIL,　the　accumulation　of　surface　charges　could　cause　electric　field　distortion　and　thus　even　cause　the　flashover.　In　the　numerical　simulation　of　surface　charge　accumulation,　only　the　charge　carriers　generated　by　natural　ionization　are　considered　in　some　of　the　studies.　But　in　fact,　during　the　operation　of　DC　GIL,　due　to　the　rough　surface　of　the　insulator　and　other　reasons,　weak　discharges　always　exist.　These　weak　discharges　are　called　micro　discharges.　In　this　paper,　the　micro　discharge　on　the　surface　of　the　insulator　is　modeled,　and　the　influence　of　the　micro　discharge　on　the　surface　charge　accumulation　time　characteristics　of　the　DC　basin　insulator　is　studied.　The　simulation　results　show　that　the　existence　of　micro　discharge　will　shorten　the　time　constant　for　surface　charge　accumulation.　©　2020　IEEE.