The　severe　arc　generated　between　the　contacts　when　the　high-voltage　DC　relay　breaks　not　only　affects　the　breaking　reliability,　but　may　even　erode　the　contacts　and　shorten　the　life　of　the　relay.　In　order　to　study　the　influence　of　mechanical　characteristics　of　the　electromagnetic　mechanism　on　the　arc,　this　paper　proposes　a　co-simulation　technical　scheme　of　the　arc　and　the　mechatronics　system,　where　the　multi-physics　coupling　analysis　software　is　used　to　establish　the　mechanism　model　and　the　arc　model　respectively,　the　multibody　dynamics　software　is　used　to　establish　the　contact　collision　model,　and　then　based　on　the　Simulink　platform　the　three　models　are　coupled　to　realize　co-simulation.　Through　the　co-simulation　of　the　system,　it　is　convenient　to　study　the　electrical　characteristics　of　the　arc　and　subsequently　the　influence　of　the　structural　parameters　of　the　electromagnetic　mechanism　on　the　arc　characteristics.　The　system　is　helpful　for　designers　to　improve　and　optimize　the　relay　product.　The　technical　solution　also　provides　a　new　idea　for　the　design　of　various　electromagnetic　apparatus.　©　2022　IEEE.