In this paper, (2H- methyl) toluene was prepared by catalysed halogen- tritium substitution method from benzyl bromide, then it was nitrated to produce (8H- 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 sudied in rats. The results showed that the toxicokinetics characteristics of TNT were quickly absorbed into the blood, Vd>2L/kg.h, long T1/2β 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 1,1- 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). In this paper, (2H-methyl) toluene was prepared by catalysed halogen- tritium substitution method from benzyl bromide, then it was nitrated to produce (8H- methyl) trinitrotoluene. At last, the pure 3H- TNT was obtained with a 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 sudied in rats. The results showed that the toxicokinetics characteristics of TNT were quickly absorbed into the blood, Vd> 2 L / kg.h, long T1 / 2β 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 1,1- 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).