The effect of Ba2+ on the crystallization thickness of calcium hexaaluminate (CA(6)) along the c axis was studied. The results show that after introduction of Ba2+, the CA(6) flake crystals fired at 1600 degrees C become thicker obviously. The structure refinement shows that the structure formula of the doped CA(6) is (Ca0.973Ba0.027)O6Al(2)O(3), indicating Ba2+ has entered the lattices of CA(6) and substituted Ca2+ in the mirror layers. The introduction of Ba2+ results in more defects V-Al in spinel block layers in CA(6), making ions easier to diffuse along c axis and fastening the growing of CA(6) crystals along c axis. Thus, the introduction of Ba2+ is feasible and advantageous to increase the crystallization thickness of CA(6) along c axis.