Abstract: ID-TIMS technique was used to measure the uranium content and uranium isotope ratios for environmental samples, in which 233U was used as spike. Compared with traditional methods in which 235U is used as spike, this method simplifies the analysis steps. Furthermore, the results of uranium isotope ratios calculated by ID-TIMS technique were well consistent with those measured directly by TIMS. For ng level uranium the precision of 235U/238U was less than 0.7%, that of 234U/238U less than 10%.