Abstract: In order to observe the Visualization of SPECT and therapeutic effect of ¹³¹I-histamine-indomethacin(¹³¹I-His-IN) in rat’s Lewis pulmonary tumor model, rats with Lewis pulmonary tumor were gavaged with ¹³¹I-His-IN. The results showed that ¹³¹I-His-IN radioactive nuclide rate of tumor area to other area step up as the time goes by， and the necrotic tissue and cells become more and more. These suggested that ¹³¹I-His-IN was an effective imaging agent which can diagnosis the primarily focus and the distant place metastasis of the tumor and do the internal radiation of the tumor.