In most gas-solid fluidized bed reactors, particle-particle interactions vary as a result of the physical and/or chemical process. However, a constant value for the particle-particle restitution coefficient, a modeling parameter that can significantly affect the predicted hydrodynamics, is normally used to describe the particle-particle interaction in the simulation with the two-fluid model (TFM). Therefore, an advanced TFM with variable particle-particle restitution coefficient was developed to simulate the complex hydrodynamics and reaction behavior in the gas-solid fluidized bed reactor. The fluid catalytic cracking (FCC) riser reactor, in which the particle-particle restitution coefficient tends to decrease during catalytic cracking reactions because of the formation of cohesive coke under high temperature, was taken as an example to illustrate the application of the advanced TFM. Simulation results indicate that the advanced TFM can successfully describe the variation of the particle-particle restitution coefficient in the computational fluid dynamics (CFD) simulation of FCC riser reactor.