Abstract: Experimental result of the effect of 90Sr on embryonic development of C. auratus and the absorption and accumulation of 90Sr by fry of C. auratus are summarized as follows:During the embryonic development of C. auratus, embryonic malformation and mortality occurred in each group of experiments. The percentage of malformation and mortality rose along with the increase of specific radioactivity. For example, in the hatching stage, it was: Control-21%; 5×10-11 Ci/1—36%; 5×10-10 Ci/1—40%; 5×10-9 Ci/1—45%.Peak-value of malformation occurred in the stage of blastula and crystalline body formation. Types of deformities were: (1) Curvatures of the vertebral column or tail; (2) Small head or malformation of head; (3) Short body or malformation of tail; (4) Edematous yolk sac and pericardium.In general, total radioactivity of absorption and accumulation by C. auratus was in direct proportion to specific radioactivity, Accumulation coefficient, however, was independent of the weight of C. auratus and the specific radioactivity of experimental solution.