Ba1-xSrxTiO3 (BST) and Ba0.6-xPbxSr0.4TiO3 (BPST) ceramics were prepared by conventional solid-state reaction method. The analysis of XRD, FESEM and Raman spectroscopy showed the effects of Pb-doping on the crystal lattice,phase transition and surface morphology of Ba0.6Sr0.4TiO3, respectively. And the temperature dependence of permittivity (ε-T properties)for all ceramics were measured at a frequency of 10 kHz. The mechanism that Curie temperature and the peak value of permittivity are modulated by Sr and Pb content in BST and BPST perovskite has been revealed. In addition, all samples exhibit a diffused phase transition (DPT), especially for the ceramic Ba0.5Pb0.4Sr0.1TiO3, which can improve its temperature stability of tunability as phase shifter than others. Some ferroelectric parameters are calculated to interpret the DPT by adopting Smolenski’s theory and Curie-Wise law. For example, the values of diffuseness exponent α,Curie constant and transition region have changed from 1.29 to 1.73, from 1.25×105 to 2.87×105 K, and from 13.2 ℃ to 22.3 ℃, respectively.