BayFexCo4-xSb12(x=0—3.0，y=0—0.7) were synthesized by a two-step solid state reaction method. The results of Rietveld refinement demonstrated that BayFexCo4-xSb12 synthesized possesses a filled skutterudite structure. The filling fraction of Ba obtained by Rietveld refinement agreed well with the composition obtained by inductively coupled plasma emission spectroscopy. Thermal parameters (B) of Ba was larger than that of Sb, and Fe/Co, indicating that Ba “rattles”in Sb-icosahedron voids. The lattice constants of BayFexCo4-xSb12 increased with increasing Ba filling fraction and Fe content. The maximum filling fraction of Ba (ymax) in BayFexCo4-xSb12 increased with increasing Fe content, and was found to be rather greater than that of Ce of La in LnyFexCo4-xSb12. The ymax varied from 0.35 to near 1.0 when Fe content (x) changed from 0 to 4.0.