For the first time, the characteristics of solid circulation rate (GS) were investigated in a three-phase (gasliquid- solid) viscous circulating fluidized bed (TPCFB). The solid circulation rate was controlled separately by adjusting the experimental apparatus as well as operating variables. Effects of primary and secondary liquid velocities (UL1 and UL2), gas velocity (UG), particle size (dp), height of particles piled up in the solid recycle device (h), and viscosity of continuous liquid media (μL) on the value of GS were determined. The experimental results showed that the value of GS increased with increases in the values of UL1, UL2, h and μL, while it decreased with increasing UG and dp in TPCFBs with viscous liquid media. The values of GS were well correlated in terms of dimensionless groups within this experimental conditions.