Recently, surfactants were frequently used in order to desorb the hydrophobic organic compounds (HOCs) from soil and to enhance the bioavailability. Among them, -cyclodextrin ($eta$-CD) is one of those. This study was performed to investigate the binding characteristics between benzene and $eta$-CD and to examine the bioavailability of benzene. First, we investigated binding characteristics between benzene and $eta$-CD in water and water/soil system. Then, we examined the effect of $eta$-CD on the biodegradation of benzene in water and water/soil system. Experimental results on the binding characteristics showed that $eta$-CD resulted in an efficient complex formation with benzene. As -CD concentration increased, the benzene concentration complexed with $eta$-CD rapidly increased to 30-40% initial benzene added, and reached the equilibrium. We also investigated the effect of $eta$-CD on the desorption of benzene from soil in the water/soil system. As $eta$-CD concentration increased, benzene concentration desorbed into water increased up to 90%. How-ever, in its application to biodegradation of benzene in water and water/soil system, the biodegradation rate of benzene did not improved in the presence of $eta$-CD compared with in the absense of $eta$-CD. This result indicated that $eta$-CD was more preferentially used as a carbon source than benzene. Therefore, for remediation of benzene contaminated soils, $eta$-CD can be used as a surfactant to desert benzene from soil, and then ex-situ chemical treatment can be applied for the remediation.