To assure that compression on the rakes of a deep corn thickener does not stop mixing, an additional circular slurry system, which activates slurry all the time, is employed and running resistance is usually decreased. However, there is still uncertainty on how circular parameters affect underflow properties. This means that the design and application of such systems lack support from scientific theories. Hence, it is necessary to create a study on how circular parameters regulate underflow parameters. Analysis of the circular system mechanism shows that its effect can be divided into two parts and the effect of the system on underflow properties is clarified. In addition, the value of underflow concentration in thickeners is solved based on calculus and finally a mathematical model is produced, which simulates the regulation of underflow properties in thickeners. Using the model, the circular parameters of underflow in thickeners are verified. The experiment indicates that the solid concentration of underflow decreases with circular underflow initiation, then tends to stabilize. Also, the volume fraction of underflow increases in the range of 0.7% -2.2% with ascending circular flow and height. In addition, the time necessary for the solid concentration to stabilize is reversely affected by underflow flow and height. The regression function obtained from experimental statistics shows excellent performance in the model when designing and analyzing circular systems for thickeners.