Abstract: The objective of this study is to examine the effects of NO3- on the respiratory rate and its key enzyme activities of roots of sweet cheery (Prunus avium L.) under waterlogging. Pot experiments were conducted to determine the respiration and key enzyme activities by using two-year-old Meizao/Colt sweet cherries which were transferred into the solutions with 0, 10, 20 and 30 mmol/L KNO3 for 5 days. The decrease of respiratory rate is alleviated by adding exogenous NO3- under waterlogging, and respiratory rate of root tissues of sweet cherry could be enhanced when NO3- concentration is increased. After the waterlogging for 2-3 days, the addition of NO3- promotes the increases of respiratory rates of Embden-Meyer-hot-Parnas pathway (EMP), Pentose Phosphate pathway (PPP) and Tricarboxylic acid cycle(TCA), and as well as the enhancements of enzyme activities of pyrophosphate-dependent phosphofructokinase (PFK), glucose-6-phosphate dehydrogenase (G-6-PDH) and malate dehydrogenase (MDH). The addition of NO3- could lessen the waterlogging damage of the sweet cherry.