Abstract: The center segregation and banded structure of the tested steels with three different carbon contents were investigated by original position analyzer for metal,direct reading spectrometer,optical microscope and electron probe microanalyzer. The results showed that the center segregation in the slab was highly associated with the banded structure in the finished product. The distribution of the center segregation in the cross section is uneven,where 1/4 width of slab shows the greatest segregation,the center is the next,and the edge hasthe slightest level. The carbon,phosphorus,sulfur,niobium and titanium element in the steel seriously segregate in the slab and with the increase of carbon content the segregation becomes worse. The distribution of the banded structure in the cross section is also uneven. The existing standard for inspecting banded structure have certain limitations for the gradation of the banded structure.