使用动态光散射法可以获得颗粒的光强加权平均粒径，以及光强加权颗粒粒度分布。为获得数量或体积加权颗粒粒度分布，提出从光强分布到数量分布转换的直接比值法。该方法首先依据Mie散射理论求解不同粒径颗粒的散射光强，然后将光强分布与对应颗粒的散射光强进行比对，获得颗粒的数量分布，进而得到颗粒的体积分布。使用动态光散射法测量得到聚苯乙烯乳胶球混合样品的光强分布，利用直接比值法将光强分布转换为数量分布和体积分布，并与扫描电子显微镜测量的数量分布进行了对比，实验数据表明采用直接比值法能够获得准确的数量分布。

The intensity-weighted average particle size and intensity-weighted particle size distribution (PSD) can be obtained by the dynamic light scattering. To get the number-weighted PSD or volume-weighted PSD from the intensity-weighted PSD, the intensity scattered by particles of different size must be taken into account. The light intensity scattered by particles of different size is calculated using Mie scattering theory. Then, the number-weighted PSD can be calculated from the intensity-weighted PSD by dividing by the scattering intensity of the particle with the corresponding size. To demonstrate this the intensity-weighted PSD of the mixed polystyrene latex particles is obtained by dynamic light scattering, and the intensity-weighted PSD is converted to number-weighted and volume-weight PSDs using this method. Scanning electron microscopy is used to get the true number-weighted PSD to compare with our results. Comparison of the two number-weighted PSDs shows that accurate number-weighted PSD can be obtained by using approach outlined.