In biological preparations, parameters such as particle size, shape, and aggregation state can reflect drug stability and serve as critical indicators for safety assessment and immunogenicity prediction. There are various methods for determining particle size and size distribution, among which light scattering method stands out as a rapid, non-invasive, and highly sensitive technique with broad application potential. Its advantages include no requirement for sample dilution, simultaneous measurement of multiple parameters (e.g., size, morphology, and aggregation state of proteins). This technology can make significant contributions to protein solution analysis, drug quality control, optimization of production processes, and drug development. This review summarizes particle size measurement methods, current applications of mainstream light scattering instruments, and how these instruments achieve measurement requirements of biomedical materials and preparations, offering calibration strategies for practical measurements to enhance measurement accuracy for biomedical materials and preparations.