Abstract: CFD (computational fluid dynamics) method was adopted to optimize the stirring structure of the reactor. Numerical simulations were carried out for different paddle structures, installation dimensions, and baffles. The results showed that for the studied calcium stearate reactor, an uniform flow and mixing behavior were obtained by using six-arc blade disc turbine (upper paddle)-three-bladed backward curved (lower paddle) paddle. The traditional wall baffle and cross-shaped bottom baffle could not only optimize the flow situation but also enhance the upward flow, awarding deposition. By tuning the installation dimensions such as two paddles spacing and lower paddle spacing from the bottom, a continuous upward flow, an uniform velocity distribution were got in the kettle. The optimized installation dimensions are 385 mm for two paddles spacing, and 320 mm for lower paddle spacing from the bottom. The results provide numerical references for the design and optimization of the reactor.