Abstract: The particulate homogenization chamber is a specialized device designed to control concentration and achieve uniform mixing. This equipment, when used in conjunction with standard particulate devices, enables the calibration of instruments measuring particulate mass concentration. Therefore, ensuring the uniformity and stability of particulate concentration within the mixing chamber is crucial for metrological calibration. Utilizing computational fluid dynamics (CFD) simulation and experimental validation, this research identifies three key factors influencing particulate mixing chamber characteristics: dilution section height, middle section height, and diversion section height. Through orthogonal experiments, these parameters were optimized, resulting in an optimal mixing effect at 50 mm dilution section height, 50 mm middle section height, and 100 mm diffusion section height. Under these conditions, the mixing performance meets the calibration requirements for most commercially available PM₁₀, PM_2.5, and other environmental air particulate mass concentration testing instruments, as well as low-concentration dust analyzers.