The bench test was conducted to investigate NOx conversion efficiency and NH₃ storage characteristics of copper-based molecular sieve and vanadium-based SCR catalysts under different temperatures, space velocities and ANRs. The results showed that the low temperature area between 200 ℃ and 250 ℃ had an obvious effect on NOx conversion and the space velocity had little influence for copperbased SCR catalyst. In addition, temperature had a remarkable influence on NH₃ storage amount, and the NH₃ storage amount of copper-based SCR catalyst decreased rapidly with the increase of temperature. NH₃ storage amount was 1.5 g/L at 200 ℃, but decreased to 0.77 g/L at 250 ℃. Compared with vanadium-based catalyst with 40%-60% conversion rate at low temperature, copper-based catalyst showed much better low-temperature performance with conversion efficiency up to 84%. Besides, copper-based catalyst had stable performance with conversion efficiency of 98% at middle temperature about 250 ℃ to 450 ℃ and could also achieve conversion efficiency of 96% at high temperature higher than 450 ℃, and the decrease scope of conversion efficiency for copper-based catalyst is minor with the increase of temperature. Accordingly, copper-based molecular sieve catalyst had better performance than vanadium-based catalyst, which should be the priority choice for the posttreatment of China Ⅵ diesel engine from a technical point of view. The basic data obtained in this test study could be used to calibrate the engine.