The research outcome of NiO additions about the phase formation, micro-structure and electrical property of BaTiO3 ceramic has been studied. X-ray diffraction never identifies any secondary phase. The average grain size of ceramics in this idea strongly relays on the NiO content. The grain size of pure BaTiO3 is regarding 75 μm, whereas BaTiO3+NiO doped ceramics sample is around 0.5 μm. The fine grain size in BTO+NiO ceramics materials might be caused by NiO existing in the grain boundary areas which lead to grain development suppression during the sintering process and results in lower densification of the ceramics. For the dielectric data, the dielectric constant (εr) of high density BaTiO3 reaches to 5650 at TC ~100oC. After adding NiO nano- articles to BaTiO3, εr value significantly found to be more stable and diffuse. More amountof NiO nanoparticles addition into BTO may be converted this ceramic to nanaocomposite materials. The dielectric behavior of BaTiO3+NiO ceramics can be explained by the response theory of composite materials. It is believed that the more amount of NiO additions are present in the type of secondary phase inclusions into BaTiO3 micro-structure and located in the BaTiO3 grain boundaries which may hinder domain wall movement adequately to decrease the dielectric constant.