Effects of NiO were studied in aspects of dielectric properties and microstructure of $0.96(0.91Pb(Mg_{1/3}Nb_{2/3})O_3-0.09PbTiO_3)­0.04BaTiO_3$ (PMN-PT-BT, PBT). The PBT was prepared by a conventional mixed oxide method using $(MgCO_3)_4{cdot}Mg(OH)_2$ instead of MgO through Lewis acid-base interaction. NiO was added in the range of 0.5 to $3.0;wt\%$ as thermally decomposable $2NiCO_3{cdot}3Ni(OH)_2$ and it seemed to enhance densification to a large extent below $1000^{circ}C$. But all the systems gave rise to ceramics with almost same relative sintered density of $96\%$ by sintering at $1000^{circ}C$ for 2 h. But it turned out that the addition of NiO was detrimental to dielectric constant but beneficial to the loss of dielectric constant.