Abstract: Soluble β-cyclodextrin prepolymer was prepared in an alkaline medium, which was grafted onto the cellulose fiber,thus obtained a new functional fiber with inclusion of benzoic acid.The stability constant and apparent thermodynamic parameters of the inclusion complex under different temperatures were determined,and its stability and releasing behavior in aqueous solution were also investigated.It is observed that inclusion reaction which is affected by Van der Waals forces is one kind of exothermic.The inclusion complex contained in the fiber is rather stable under 20 ℃,and its release of benzoic acid reaches nearly optimum state around 37 ℃.