Abstract: Annular wetland is the mostcommon landscape type in the Sanjiang Plain.There were high potential energy areas and low potential energy areas in different microtopographies.Along with the change of potential energy,different water temperature distribution zones were formed.In these areas,the soil vegetation animal system has its features of horizontal and vertical structure.Considering horizontal distribution feature,from the center to the outer part of the annular wetland,topography is gradually higher;water gradually decreases temperature gradually rises soil changes from peat soil to marshy soil and lessive,and vegetation changes from Utricularia intermedia to Carex pseudocuraica,Ass. Carex rhynchophysa Menyanthes trifoliata,Ass. Carex lasiocarpa Glyceria spiculosa,Ass. Salix brachypoda Salix myrtilloides Calamagrostics angustifolia and Ass. Quercus mongolica Betula platyphylla. Animal's horizontal structure also had relevant changes.There were different vertical structures among horizontal distribution areas of annular wetlands.Due to their special structure,annular wetlands have correlated functions such as water storage and temperature adjustment.In addition,annular wetlands were solar energy storage and inherit gene storage.Annular wetland is important components in the Sanjiang Plain.Fully understanding of its structures and functions is important for the research of wetland ecosystem's protection and wetland resources sustainable development.

Key words: Pseudoperonospora cubensis, Temperature, Humidity, Potentiality of producing sporangia