Abstract: Rapid determination of nitrite and nitrate in triethylenediamine cobalt solution was established. Nitrate was detected by thymol method,and nitrite was measured by the improved GB 13580.7-92. Linearity range for nitrate was within 8 mg·L-1,and 0.03-0.8 mg·L-1 for nitrite. The correlation coefficients for nitrate and nitrite were 0.999 9 and 0.999 4,respectively. Values of recovery measured by standard addition method were in the range of 99.9%-108% for nitrate with RSD (n=7) of 1.2%. For nitrite,the recovery rates were 99.5%-107%,with RSD (n=7) of 1.4%.