In order to study the effect of coexistence of Nd2O3 and Sm2O3 on phase development in Ba4 (Sm0.7Nd0.3)9.33Ti18O54 ceramics, the calcination process was applied in one-step and two-step way. From the XRD patterns of one-step calcinated powders, the solid-state reactions were deduced. And the results indicated the coexistence of Nd2O3 and Sm2O3 would be helpful to form secondary phase Nd2Ti2O7, which would worsen the properties. The final tested results of sintered samples confirmed the advantages of two-step calcination. The εr was improved from 72.1 to 82.4 and Q.f was improved from 7200 GHz to 8300 GHz, while τf was still near zero.