The velocity distribution and circulation flow rate in a draft-tube stirred tank of 0.8 m diameter were studied experimentally and were numerically simulated using the FLUENT6.2 computational fluid dynamics (CFD) package. A renormalization group (RNG) k-epsilon turbulent model and multiple reference frame (MRF) were used in the simulation. The circulation now number and liquid velocity predicted by CFD were in good agreement with experimental values. Both experimental and simulation results show that the axial velocity is far larger than radial and tangential velocities inside and outside the draft tube, and there is a secondary circulation zone close to the outside wall of the draft tube, which could affect the efficiency of the tank. The results are to be of reference for the industrial stirred tank with a draft tube.