Abstract: Streptomycin albumin microspheres were prepared by polymeric dispersing agents. Some physical properties including the size, distribution and surface state of the microspheres were determined. The results showed that the diameter of the microspheres ranged from 10 to(30μm and the content was 20.3±0.5%. Drug release from the microspheres was performed by a dynamic dialysis system. Tissue distribution of streptomycin albumin microspheres in rats was studied by both fluorescein isothiocyanate and ¹²⁵Ⅰ labelled microspheres. The experiments revealed that the major part of the microspheres accumulated in the lung following intravenous injection. The effectiveness and side effects of the streptomycin in the microspheres remain to be determined.