Abstract: The rolling technology of large size tantalum sheets with width ≥ 600 mm, length ≥ 1 000 mm, and thickness=2~15 mm is studied, and the causes for the "tongue shape" or "defect in corner" at tantalum sheet end during the rolling process are analyzed. In the experiment, by multiply changing the rolling direction, controlling the thickness reduction rate, and adopting the rolling precompensation for "defect in corner" along the diagonal direction of the tantalum sheet, the large size tantalum sheet(1 000 mm×600 mm×4 mm) with indent "tongue shape" and compensated "defect in corner" is prepared. This method increases the material yield by 7% or more, improves the product quality, and reduces the cost, which will enhance the market competitiveness of products.