The Bi 2Pb(Sr 2− x Ba x )Ca 2Cu 3O y samples with x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5 were prepared by the solid-state reaction and analyzed by DSC, ICP, EPMA, XRD and IR, and their resistivity and a.c. susceptibility were also measured. The Ba 2+ ion is substituted successfully for the Sr 2+ ion in the 2223 phase with the solubility of Ba 2+/Sr 2+ = 0.15 in the BiPbSrCaCuO system. In this range, the c-axis and the unit cell volume are increased and the distance of BiO(Sr)Cu bond is increased with the increased of Ba-content. The transition temperature is enhanced a little and the transition width is narrowed with increasing in Ba-content within the solubility range. From the above results, it is inferred that the SrO layer in the structure is not involved directly in the superconducting mechanism and that the role of SrO layer is to confine the superconducting electrons in two-dimension.