Several experiments have been conducted to assess the possible mechanisms for the inhibition of reduction of Ca2+-doped barium titanate in a reducing atmosphere. Three methods, i.e., conventional, semiwet, and citrate processes, have been used to prepare the powders. It was found that the formation mechanism would influence the occupation of Ca2+ in the B site. Moreover, it was concluded that Ca2+ occupation of the B site is the major cause for the inhibition of reduction of Ca2+-doped barium titanate. Ti deficiency would be the driving force for Ca2+ to occupy the B site.