The Cu/SAPO-34-z catalyst was prepared in situ by using triethylamine phosphate as the structure director and phosphorus source. The catalytic activity was investigated before and after 800 ℃-10%-24 h treatment. The physicochemical properties were analyzed by XRD, SEM, TG and BET, and the engine bench performance was further verified. The results showed that SAPO-34 prepared with triethylamine phosphate had higher crystallinity, the specific surface area was 682 m²/g, and the particle size was concentrated in 1-3 μm. In the roasting process, the weight loss at 350-450 ℃ becomes serious due to the decomposition of copper-ammonium complex. High-temperature hydrothermal treatment had little effect on the lowtemperature activity of Cu/SAPO-34-z catalyst and the activity window degraded from 173-515 ℃ to 173-445 ℃.The bench performance test results showed that the NOx conversion of selfdeveloped SCR samples exceeded 90% at 200 ℃ and approached 100% at 220-450 ℃. Even if the space velocity increased to 60 000 h-1, the NOx conversion still exceeded 98%. The effect of temperature on ammonia storage was much greater than space velocity. The decreases caused by temperature were 86%, 86% and 57.5% respectively under the three space velocities. The higher the ammonia storage, the higher the NOx conversion, and the lower the influence of fluctuation range on temperature and space velocity. The higher the space velocity, the higher the ammonia escape. The higher the temperature, the smaller the difference of ammonia escape before and after stopping the urea injection.