Abstract: By applying photosynthetic bacteria under the ice of overwintering pond,the experiment about the effect on fishes in winter was carried out in Minfu fishery base of Heilongjiang viver Research Institate.By analyzing water quality regulary and commparing the overwintenig Survival rate,the resules showsthat The fluctuattion of dissowed oxygen and the biomass of plandto under the ice of overwintering jpond in witer by applying photosynthetic bacteria is very little,and water quality is also cleaned,physical and chemical factos in overwinterig waters remain steble,which make fishes live through the winter safely.

Key words: photosynthetic bacteria, overwintering pond, dissolved oxygen, plankto