Na²¹¹ At and ²¹¹At-Te colloid injections are prepared. It has been demonstrated that the ²¹¹At-Te colloid is stable in vivo and vitro, and can be applied in the study of biology and medicine. In the report, the model of Murine Ehrlich Ascites Cells cultured in vivo and vitro is elected for a series of experiments. It has been proved that Na²¹¹ At and ²¹¹At-Te colloid injections possess an inhibition effect on tumor cells. The inhibition effect was expressed in surviving of the mice and inhibiting growth of tumor as well as the changes of enzyme activity. Meanwhile, it was also noticed that Na²¹¹ At and ²¹¹At-Te colloid injections of various dose inhibited the absorb of pyrimidine nucleosides in Murine Ehrlich Ascites Cells. And the effect isn't reversible. It is closely related to the dose administratered and 50% inhibition rate needs about 1.48×10⁵ Bq/ml culture.