In the present work, detached eddy simulation (DES) of the turbulent flow in an unbaffled stirred tank agitated by a six-pitched-blade turbine was carried out. The sliding mesh (SM) approach was applied to simulate the rotation of the impeller. For comparison, the computations based on the large eddy simulation (LES) model and RANS equations closed with Reynolds stress model (RSM) were also performed. The instantaneous velocity fluctuations, mean velocity and turbulent kinetic energy profiles were analyzed and compared with the laser doppler velocimetry (LDV) results from literature. Results show that DES model can capture the unsteady turbulent flow characteristics accurately. The mean velocity and turbulent kinetic energy profiles by the DES model are in good agreements with the LES results and the LDV data. Besides, the computational cost of DES is only about 80% of LES. By contrast, the results obtained by RSM are not so good. It can be concluded that the DES model can produce as similarly good predictions as LES with less computational cost, and can work as an alternative of the LES model in predicting the hydrodynamics in the stirred tanks.