Abstract: Using Model 235 high volume cascade impactor to gather samples in the atmospheric particulates (PM₁₀) of Shanghai and Hengyang. ²¹⁰Bi and ²¹⁰Pb finally get decay balance in the decay chain. After comparing with γ-spectrum method, this study chose the low-background β counting method to calculate the size distribution of ²¹⁰Pb in the different atmospheric particulates. The experimental results show that in the Shanghai and Hengyang, radioactivities of ²¹⁰Pb at different particle size ranges distribute very unevenly in the atmospheric particulates. About 91.58%, 91.37% of the ²¹⁰Pb activity are adsorbed on PM_1.5. After comparing with the result through γ-spectrum method of low-background inverse compton effect, ²¹⁰Pb activity presents similar size distribution in the atmospheric particulates.