Abstract: The aging chamber is an important part of the reliable control of the ²²⁰Rn chamber, and its optimized design is one of the key technologies to establish a high-level ²²⁰Rn chamber. Based on the existing the aging chamber of University of South China and previous studies, this paper uses computational fluid dynamics to establish the aging chamber numerical model, and analyzes the effect of the inlet flow rate, the axial length of the aging chamber and the air exchange rate on the performance of the aging chamber. The performance simulation results were compared with experiments, and finally the optimization analysis of the aging chamber was carried out. The results show that: The laws obtained by simulation and experiment are consistent, and the relative error between simulation results and experimental results is kept within 11%; Increasing the inlet flow rate can effectively improve the uniformity and stability of the aging chamber, and increase aerosol activity output rate of the progeny of ²²⁰Rn of the aging chamber; When the axial length is constant, the inlet flow rate increases from 1 L/min to 10 L/min, and the time for the aerosol concentration of the progeny of ²²⁰Rn of the aging chamber to reach a steady state can be shortened by 66.41% at the maximum. The aerosol activity output rate of the progeny of ²²⁰Rn of the aging chamber can increase by 20.25% at the maximum. The uniformity of the aging chamber gets worse and then becomes better, and the uniformity is the worst when the inlet flow rate of the aging chamber is 4 L/min. Increasing the axial length of the aging chamber has little effect on the uniformity and stability of the the aging chamber, but it can effectively increase the aerosol activity output rate of the progeny of ²²⁰Rn of the aging chamber. When the inlet air flow rate of the aging chamber is set to 1.10 L/min and kept constant, and the axial length increases from 100 cm to 140 cm, the time for the aerosol concentration of the progeny of ²²⁰Rn to reach a steady state does not change significantly, and the aerosol activity output rate of the progeny of ²²⁰Rn can increase by 48.51% at the maximum. The uniformity of the aging chamber gets worse and then becomes better.