The modified UV spectrophotometry and cadmium reduction method (flow injection analysis) are two main methods applied to rapid analysis of NO₃^- -N. To explore the difference and application in the measurement of NO₃^- -N by the two methods, 10 soil samples from different regions of China were determined by the two methods. Results showed that significant correlations existed between NO₃^- -N contents determined by the two methods, the precision of the two methods ranged from 89% to 104%. There are difference in methods application depend on the content range, for low content of NO₃^- -N, cadmium reduction method was better than UV spectrophotometry in accuracy, but for high content of NO₃^- -N, UV spectrophotometry was better with higher precision and lower variability, and the measured value using UV spectrophotometry method were higher than that using cadmium reduction method. UV spectrophotometry was more suitable for rapid analysis of large batches of soil samples for its simple operation and less interference factors.