Industrial trials detailed in a riser-downer coupling reactor proposed for the fluid catalytic cracking (FCC) process are presented in this paper. The trials are based on the fundamental research of hydrodynamics, mixing behaviors, and laboratory-scale hot experiments described in our previous investigations. Compared with the riser reactor with the same feeds and catalyst, the LPG and propylene yield increased by 8.15 and 4.30 wt %, respectively. The gasoline octane number likewise reached 94.8 with 28 wt % olefin content. However, dry gas is significantly suppressed, and the coke has little change in yield even with the increased catalyst to oil ratio. With some gasoline recycling, the LPG and propylene yield increased by 11.45 and 5.06 wt %, respectively, and the olefin content in gasoline significantly decreased to 22 wt %; the high octane number (95.4) is maintained. The computational fluid dynamics (CFD) coupled with a 6-lump kinetic model is also applied to simulate the FCC process for the industrial trials. The yield of propylene and butylene and the temperature profile along the axis direction demonstrated consistency between the simulation results and the experimental data.