In this study,a novel technique for the preparation of 125I-5-trimethylstannyl1-(2-deoxy-2-fluoro-beta-D-arabinofuranosyl) urail (FIAU) was developed,125I-FIAU biodistribution profile was detected in Kunming mice and the possibility of using FTAU radio-labeling for reporter gene imaging was explored.5-trimethylstannyl-l-(2-deoxy-2-fluoro-beta-D-arabinofuranosyl) urail.(FTAU) was labeled with radioiodine (125I).A rotary evaporation method was used to remove excess methanol.The reactant was purified through a Sep-Pak C18 reversal phase column.The radiochemical purity and in vivo stability were determined using silica gel thin layer chromatography (TLC).The biodistribution of 125I-FIAU in Kunming mice was also detected.The results showed that 125I-FIAU could be radiolabeled effectively with FTAU,with mean labeling rate being (81±0.38)％ (n =5).The mean radiochemical purity of (98.01±0.40)％ (n=5) was achieved after a reversal phase Sep-park column purification.125I-FIAU was stable when incubated in normal human serum or in saline at 37℃,with a radiochemical purity ＞96％ during a 0.5-24 h time period.Biological experiments exhibited rapid clearance of 125I-FIAU from the blood pool.125I-FIAU was mostly excreted by kidneys.125I-FIAU in myocardium dropped conspicuously after 8 h and there was hardly retention at 24 h.We were led to concluded that the new method of radioiodinization of FTAU for the preparation of 125I-FIAU is easy,highly effective and stable in vivo.The biodistribution of 125I-FIAU in Kunming mice showed it can serve as an imaging probe for myocardial reporter genes.