A simple size-exclusion high-performance liquid chromatographic method was developed for rapid molecular mass screening to determine the average molecular mass, polydispersity, and quantity of Taizishen polysaccharides extract. The screening used a TOSOH TSK-GEL G3000SW high-performance liquid chromatographic column with 0.1 mol/L NaNO₃ buffer as the mobile phase and refractive index detector. The molecular mass calibration curve was linear for polysaccharide standards from 10 to 100 kDa with a correlation coefficient of 0.9991. The method can be used to analyze the quantity, average molecular mass, and polydispersity of polysaccharides. In addition, the screening method is suitable for quality control of polysaccharide preparations in Chinese medicines and pharmaceutical products.