Monoxide　and　dioxide　of　animo　quinoxaline　were　synthesized　and　characterized　by　H-1　NMR,　C-13　NMR　and　HRMS.　The　result　shows　that　monoxide　is　main　product.　H-1　NMR　analysis,　quantum　calculation　and　crystal　structure　all　indicate　that　the　monoxide　is　4-oxide　structure　but　not　1-oxide　structure.　The　subsequent　discussions　of　electronic　effect　and　steric　effect　of　1-oxide　and　4-oxide　support　the　conclusion　that　4-oxide　is　dominant　product,　which　is　consistent　with　H-1　NMR　analysis　and　crystal　structure.　At　last,　the　calculated　structure　is　in　good　agreement　with　the　crystal　structure　in　this　paper,　which　indicates　that　the　calculation　result　in　this　paper　is　credible.　(C)　2020　Published　by　Elsevier　B.V.