The invention discloses a catalytic cracking unit. The catalytic cracking unit mainly comprises a heavy oil descendent tube reactor, a light hydrocarbon descendent tube reactor, a precipitator, a riser regenerator, a turbulent bed regenerator and the like, wherein the turbulent bed regenerator is communicated with the precipitator respectively through the heavy oil descendent tube reactor and light hydrocarbon descendent tube reactor; the precipitator is communicated with the riser regenerator; and the riser regenerator is communicated with the turbulent bed regenerator. The unit can improve the catalytic cracking product distribution, enhance the light oil yield and lower the yield of the cracked gas and coke; the unit can be used for producing low-olefin-content catalytic gasoline and high-cetane-number catalytic diesel; and the unit enhances the charring efficiency and decelerates the hydrothermal inactivation of the catalyst.