Abstract: The mixture model and the multiple reference frame (MRF) were used to simulate the flow field in a CK stirred tank to analyze the internal flow field characteristics. The results showed that the flow field of CK stirred tank was mainly composed of one main circulation flow and two small circulation flows. The fluid in stirred tank undergone upward and downward circulation followed the "W" cycle trajectory. The pressure on the top and bottom of the tank was the highest and then gradually decreased towards to the stirring center, and the pressure distribution can facilitate mixing. A short mixing time was obtained with increasing stirring speed. The critical suspension speed of the stirred tank was 130.51 r/min. When the stirring speed reached 190 r/min, the solid phase in stirred tank could be uniformly suspended after the blade ran 100 r, which indicated that the stirred tank had a high stirring efficiency.