The　operation　effect　and　carbon　emission　characteristics　of　the　A2/O+MBR　process　in　the　H　reclaimed　water　plant　of　Tongzhou　District,　Beijing,　were　studied　in　this　paper.　The　results　showed　that　the　average　removal　rates　of　BOD5,　CODcr,　NH4+-N,　TN　and　TP　were　97.3%,　94.1%,　98.6%,　77.0%　and　96.2%　respectively.　The　total　carbon　emission　and　carbon　emission　per　ton　of　water　of　the　H　reclaimed　water　plant　decreased　gradually　in　spring　and　summer　and　increased　slowly　in　autumn　and　winter,　the　total　carbon　emission　per　ton　of　water　was　about　2.26kgCO2e/t.　In　the　total　carbon　emissions,　energy　consumption　carbon　emissions　accounted　for　the　leading　position,　while　CH4,　N2O　carbon　emissions,　and　drug　consumption　carbon　emissions　accounted　for　a　relatively　small　proportion.　The　statistical　analysis　results　showed　that　the　carbon　emissions　of　CH4　ton　water,　energy　consumption　ton　water,　and　material　consumption　ton　water　were　significantly　correlated　with　BOD5,　TN　influent　concentration,　and　BOD5　removal　rate.　The　carbon　emission　of　N2O　per　ton　of　water　was　significantly　correlated　with　the　influent　concentrations　of　TN　and　BOD5.　There　is　no　significant　correlation　between　direct　and　indirect　carbon　emissions　per　ton　of　water　and　water　quantity.　©　2021,　Editorial　Board　of　China　Environmental　Science.　All　right　reserved.