Abstract: The seasonal dynamics of the acanthocephalan Micracanthornhynchina motomurai in the three small cyprinids,Opsari2ichthys uncirostris, Zacco platypus and Hemiculter bleekeri bleekeri in the Danjiangkou reservoir was investigated from February2004 to February 20051 The prevalence and abundance of the acanthocephalan exhibited very similar and significantly seasonalchange patterns in O. uncirostris and H. bleekeri bleekeri. The infection levels were higher in autumn and winter,but lower inspring and summer. However,the infection levels in Z. platypus kept stable all the year round. There were significant differencesamong the overall abundance of the acanthocephalan in the three host populations.Nevertheless,the frequency distribution of theparasite in the three kinds of fish was over-dispersed in most seasons and in total as measured by the variance to mean ratio. Thevariance to mean ratio was not found related to the infection levels.