In recent 10～20 years,the discovery of prochlorophyte and microbial food web has revealed the significance of nano\|plankton in nutrient cycle and energy flow of aquatic ecosystem.In this paper,the improvement of the researches on the main groups of nano\|plankton,i.e.,nano\|phytoplankton and ultr\|phytoplankton,heterotrophic bacteria and nano\|zoolplankton was briefly reviewed,and then the ecological relationship among the main groups and the studies on microbial food web were discussed.Additionally some i...