A　sleeve-type　mechanically　stirred　ammonium　magnesium　phosphate　crystallization-inclined　plate　enhanced　precipitation　reactor　was　developed　to　treat　wastewater　containing　high　concentration　of　nitrogen　and　phosphorus,　and　recover　ammonium　magnesium　phosphate　crystals.　The　effects　of　stirring　speed,　hydraulic　retention　time　and　total　number　of　particle　collisions　(GT　value)　on　reactor　performance　were　investigated.　The　computational　fluid　dynamics　software　(Fluent　18.1)　was　used　to　conduct　numerical　simulation　of　the　flow　pattern　in　the　reactor,　and　the　rationality　of　reactor　structure　design　was　analyzed.　This　would　provide　technical　reference　for　the　design　and　operation　of　the　ammonium　magnesium　phosphate　crystallization-precipitation　reactor.　The　results　indicated　that　the　average　recovery　of　ammonia　nitrogen　and　phosphorus　was　above　76.00%　and　97.00%,　respectively,　when　the　stirring　speed　was　250r/min,　the　hydraulic　retention　time　was　0.375h,　and　the　average　GT　value　was　from　14,000　to　20,000.　Under　such　operating　conditions,　the　average　particle　size　of　crystal　reached　20.515μm,　and　the　turbidity　of　effluent　was　below　2NTU.　The　results　of　scanning　electron　microscopy　and　X-ray　diffraction　showed　that　the　precipitate　in　the　reactor　was　pure　magnesium　ammonium　phosphate.　There　was　an　obvious　hydraulic　grading　in　different　areas　of　the　reactor,　with　a　turbulent　flow　pattern　in　the　mixed　reaction　crystallization　zone,　a　transition　flow　regime　in　the　buffer　zone　and　the　collecting　zone　of　magnesium　ammonium　phosphate,　and　a　laminar　flow　pattern　in　the　solid-liquid　separation　zone.　The　flow　characteristics　of　the　reactor　showed　that　its　structural　design　could　meet　the　hydraulic　requirements　for　crystal　formation　and　growth　as　well　as　the　solid-liquid　separation　under　suitable　operating　conditions.　©　2020,　Editorial　Board　of　China　Environmental　Science.　All　right　reserved.