Abstract: The benthic fauna and biodiversity surveys were carried out in Zhalong Nature Reserve located in the Songnen Plain, the first nature reserve for red-crowned cranes and other large waterfowls and wetland ecosystems, in the spring, summer and antumn of 2008. The results showed that the benthic fauna were composed ofArthropoda, Mollusca and Armelida, and a total of 93 species （gen- era） were observed in Zhalong Wetland. The maximal number of macrobenthos species was found in spring and autumn months, and the minimal number of species in summer. The Margalef species richness index （d）, Shannon-wiener index （H＇） and Pielou evenness index （J） for the benthic fauna were found to be the maximum in spring and the minimum in summer; Sirmpson dominance index （D） , however, was found to be the maximum in summer, followed by in autumn, and the minimum in spring.

Key words: Zhalong Wetland Nature Reserve, macrobenthos, species diversity