Abstract: The nature of degradability and innocuity makes chitosan a kind of excellent cationic organic flocculant. The flocculant mechanism，influence factors (such as molecular weight，pH，initial turbidity，organics and ion concentration)，flocculation efficiency and modification of chitosan are discussed. The modified chitosan which overcomes some of its defects，could be widely applied in the future.

摘要： 综述了壳聚糖絮凝机理、絮凝影响因素（分子量、pH值、初始浊度、有机物、离子浓度等）、絮凝效率及壳聚糖改性等方面的内容。改性后的壳聚糖能较好地克服自身的一些缺陷，具有较广阔的应用前景。