The sintering and electrical properties of the hydrothermal PSZT powders obtained by substituting 4, 6 and 8mol% Sr for Pb in PZT lattice structure were investigated. The lattice constant and particle size decreased in proportion to a quantity of Sr. The sintering properties of PSZT powders showed $7.754g/cm^3$ of sintered density and $4{mu}m$ of grain size at sintering temperature of $1250^{circ}C$. Curie temperature lowered gradually from $363.6^{circ}C;to;319.2^{circ}C$ and relative dielectric constants increased rapidly by a quantity of Sr. In comparison to PZT, moreover, the quality factor of PSZT was increased more than three times with increase of Sr mole ratio, and piezoelectric constant $(d_{31};and;g_{31})$ was decreased. It was found that dielectric loss of PSZT was decreased by 0.574% which was half of PZT.