In this paper,the effect of extraction of onion to removal nitrite was studied in a series of experiments.The properties and stability of extraction of onion solution were observed.The removal rate of by extraction of onion was determined,and its affecfing factors(i.e.reaction time,value of pH,the concentratioi of extraction of onion solution etc) were studied.The results indieate that the removal rate of nitrite by extraction of onion was high,but the the properties of extraction of onion solution were instable,and the removal rate was easily affected by various factors.