Abstract: The sample (0.100 0 g) of nuclear grade sponge zirconium was dissolved with HF (0.5 mL) and HNO₃ (2 mL) at temperature of 150℃ or so,and then was diluted to 100 mL with water. ICP-MS was applied to the determination of W in the sample solution. ¹⁸⁴W was used as the analytical nuclide, ²³²Th was used as internal standard. Linearity range of W was found in the range within 100.0 μg·L^-1 with detection limit (3s) of 0.003 μg·L^-1. Tests for recovery was made by standard addition method at the concentration levels of 2.00, 50.00 μg·L^-1, values of recovery found were 91.5%,93.5%, with RSD's (n=6) of 5.0%, 2.4%.