The patterns and characteristics of radial oxygen loss（ROL）under natural, aerobiotic and anoxic conditions were investigated respectively by the standard oxidized dye (methylene blue agar)method. And the characteristics of pore and oxygen loss barriers were observed by using the front stand fluorescence microscope. Based on these experiments, the effects of oxygenation conditions on treatment of swine waste water controlled by canna floating bed technology were analyzed. ROL is very low in any pot in aerobiotic conditions, and it reaches its peak in root apex zone and declines dramatically along the rhizel in anoxic condition. ROL is high in every pot under natural conditions. Corresponding to the higher ROL, the pore is bigger and the oxygen loss barrier is thicker. ROL makes water aerobiotic. The removal rates of NH3-N and TN were 62.36% and 47.9% respectively by taking canna floating bed technology, and NO3+-N accumulated and increased under aerobiotic condition.