Three　amphiphilic　CTS　were　used　for　PosiDAF　algal　removal　experiment,　and　the　algal　removal　effects　under　different　conditions　were　compared　to　explore　the　algal　removal　mechanisms.　The　results　showed　that　the　amphiphilic　modification　can　enhance　the　water　solubility　of　CTS　while　reduce　the　thermal　stability　of　CTS.　The　significant　degree　of　influence　on　the　responding　value　(substitution　degree)　was　as　follows:　carbon　chain　length＞reaction　time＞reaction　temperature＞raw　material　feeding　ratio.　When　the　1.0mg/L　N-2hydroxypropyl　trimethyl　chitosan　ammonium　chloride　(C4-HTCC)　was　used　as　modifier,　the　effectiveness　of　algae　removal　was　the　best,　reaching　93.47%;　because　the　modified　microbubbles　have　strong　electrostatic　attraction.　©　2022　Chinese　Society　for　Environmental　Sciences.　All　rights　reserved.