To　explore　the　synergistic　effects　of　modified　biochar　in　the　purification　of　herbicide-containing　wastewater,　the　effect　of　biochar　addition　on　the　removal　effect　of　the　herbicide　atrazine　in　wastewater　was　verified　by　the　addition　of　biochar　bags　in　a　small　reed　bed-constructed　wetland　in　the　laboratory.　The　results　showed　that　the　addition　of　sulfuric　acid-modified　biochar　could　increase　the　removal　rate　of　atrazine　in　wastewater　from　50%　to　70%,　and　the　COD　elimination　rate　in　wastewater　was　from　66.7%　to　86.7%.　The　addition　of　biochar　to　the　constructed　reed　bed　wetland　improved　the　removal　efficiency　of　total　nitrogen　and　total　phosphorus　in　the　wastewater,　and　the　outlet　water　from　the　constructed　wetland　reached　the　Class　III　level　of　China’s　surface　water　quality　standard　(the　inlet　water　was　inferior　to　Class　V).　The　experimental　design　met　the　requirements　of　low-cost,　generalized　atrazine-containing　wastewater　treatment　and　thus　could　have　the　potential　for　wide　application.　The　results　reflected　the　application　potential　of　modified　biochar　as　a　synergist　in　the　treatment　of　herbicide　wastewater　in　constructed　wetlands.　©　2022　by　the　authors.