The effect of reactive temperature and space velocity on the storage-release characteristics of NH3 was investigated on the dynamic reaction model of SCR catalytic reaction. The result has shown that the storage amount of NH3 increases with the increase of reactive temperature, the impact of reactive space velocity on NH3 storage amount shows different characteristics in different temperature ranges, the decreasing trend of NH3 storage amount increases with the increase of reactive space velocity when the temperature is between 200 ℃ and 300 ℃, and the decreasing trend of NH3 storage amount decreases with the increase of reactive space velocity when the temperature is over 300 ℃. Reactive temperature and space velocity also have effect on the storage and release velocity of NH3.