Abstract: The important applications of scanning electron microscopy (SEM) in the characterization of controlled release microspheres are reviewed. The SEM method was used to characterize the microspheres, and the SEM-based automatic particle shape and size analysis software was used to perform statistical analysis of the microspheres, and the key application scenarios of SEM in the scientific research or development of microspheres were summarized. Microspheres are a type of formulation that is highly dependent on structure, and its performance and therapeutic effects are largely determined by their microscopic features such as structure and porosity. The size, particle size distribution and shape of microspheres play a decisive role in the drug release. Due to the characteristics of high drug loading, the interbatch consistency of microspheres is particularly important. Image analysis tools are of great significance for the characterization of interbatch consistency. SEM has the advantage of what you see is what you get, and can quickly evaluate the particle size, shape and surface roughness of microspheres intuitively. The results showed that the SEM has a wide application value in the production control and development of microspheres, and provides an advanced characterization tool for research and development of this type of preparation.