Abstract: Pharmacokinetics of 3H-IN in tumor-bearing Mice’s blood and tumor are studied, and the accumulated phenomenon of IN in tumor are further discussed. mice are taken out blood and tumor at different time point after being taken 3H-IN orally, radioactivities are counted and concentrations of IN are measured in the tissues above.The results show that 3H-IN accumulated in tumor tissue with high levels for long time,But at the same time IN prototype is cleared rapidly and the concentrations are far lower than in blood, pharmacokinetic parameters were calculated by DAS ver1.0 software. The results demonstrate that 3H-IN has good affinity to the tumor tissue and the major part accumulated in tumor is not the IN prototype.