The X-ray diffuse diffraction patterns of BaPb1-x Bix O3 with 0.05 ≦ x ≦ 0.30 were measured. The evidence of the existence of the small spheres in the uniform background matrix was found in agreement with the previous SEM report. The experimental diffraction pattern of the small spheres is compared with the calculated one of orthorhombic structure of space group Pnma with lattice constants a = 8.784 Å, b = 4.774 Å, and c = 5.952 Å.