Abstract: Described in the article is the calculating formula and calculation sheet used by the author for W. T. of empty-sunken steel tubes. Accuracy analyses are also conducted here. The investigations made on 49 cases show that the average error is 2.30%, and the positive rate of judgement of the W.T. variation nature is 95.5%, and that of the empty-sinking die angle, friction factor and the tube material/shape have little effect on the result of the calculation.