Four groups of barium titanate (BaTiO3) ceramics with high piezoelectric coefficient have been successfully fabricated from different raw materials. Their average grain size (g) dependences of the piezoelectric coefficient d33 were systematically studied. It was found that for two groups of BaTiO3 ceramics, d33 firstly increases and then decreases with the increase of g, with a maximum d33 of 449pC/N and 501pC/N respectively at approximately 1µm grain size, while for the other two groups of BaTiO3 ceramics, d33 keeps increasing with the increase of g. The highest d33 of 401pC/N and 424pC/N were obtained when g is larger than 50µm. The experimental results indicated that piezoelectric grain size effect in BaTiO3 ceramics may be not absolute. Possible mechanisms arising from differences in domain configuration were discussed.