In this paper, (³H- methyl) toluene was prepared by catalysed halogen- tritium substitution method from benzyl bromide, then it was nitrated to produce (³H- methyl) trinitrotoluene. The tritiated product was purified by thin- layer chromatography. At last, the pure ³H- TNT was obtained with specific radioactivity of 3.77 GBq/mmol. Radiochemical purity was over 98% and the ultraviolet absorption spectrum of tritiated TNT was conformed with that of standard sample. Using ³H- TNT as a tracer, its toxicokinetics was studied in rats. The results showed that the toxicokinetics characteristics of TNT were quickly absorbed into the blood, V_d > 2L/kg.h, long T_1/2 β and fixed accumulation with four routes of administration, TNT and its metabolites were mainly excreted by the urine. The half- life of TNT in the urine were 11- 24h. A trace of radioactivity of ³H- TNT and its metabolites could be detected in the urine on 7th day after administration (9.25 × 10⁶Bq/kg).