Inclusion distribution in ingots was studied by dissection of a 16.8tP12ingot and a 5.0tH13ingot,with the analysis of T[O],original position statistic distribution analysis(OPA),metallographic microscope static analysis and small sample electrolysis.The results showed that the inclusions in ingots were uneven;apositive segregation area was found in the center and lower part of the ingot,while a negative segregation area was present in the central part of ingot top;inclusion segregation in a large size ingot was severer than that in a small one.A new concept,named inclusion segregation index,was put forward to quantify the segregation degree of inclusion.It was found that the segregation indexes drawn from T[O]analysis and OPA fit well,but they were different from those obtained by metallographic microscope static analysis and small sample electrolysis in the investigation of P12ingot,which contained a higher sulfur content;while the segregation index drawn from T[O]analysis was close to that from metallographic microscope static analysis in the H13ingot with a lower sulfur content. Inclusion distribution in ingots was studied by dissection of a 16.8tP12ingot and a 5.0tH13ingot, with the analysis of T [O], original position statistic distribution analysis (OPA), metallographic microscope static analysis and small sample electrolysis. The results showed that the inclusions in ingots were uneven; apositive segregation area was found in the center and lower part of the ingot, while a negative segregation area was present in the central part of ingot top; inclusion segregation in a large size ingot was severer than that in a small one . A new concept, named inclusion segregation index, was put forward to quantify the segregation degree of inclusion. It was found that the segregation indexes drawn from T [O] analysis and OPA fit well, but they were different from those obtained by metallographic microscope static analysis and small sample electrolysis in the investigation of P12ingot, which contained a higher sulfur content; while the segregation index drawn from T [O] analysis was close t o that from metallographic microscope static analysis in the H13ingot with a lower sulfur content.