PbZr_0.52Ti_0.48O₃(PZT) ferroelectric thin films were deposited on LaNiO₃ coated p-Si(111) substrates by RF magnetron sputtering at low substrate temperature( T =370℃) with deposition power ranging from 60W to 120W, sequentially followed by a rapid thermal annealing(RTA) process at temperature 650℃ for 5 minutes. The crystalline phase, microstructure, composition, and electrical properties of PZT thin films were investigated by X-ray diffraction(XRD), canning electron microscope(SEM), inductively coupled plasma-atom emission spectrometry (ICP-AES), four-probe meter and spectro-ellipsometer, respectively. It is found that the microstructure, composition and electrical properties of sputtered PZT thin films are highly dependent on the deposition power, i.e., the atom rate Pb(Zr+Ti) of PZT films and the leak-current of Pt/PZT/LNO capacitors increase as the deposition power increases, films deposited at low power are Pb-poor and present nonferroelectricity, while those deposited at high power are Pb-rich.Optimized deposition power is 80W.