The characteristics of the spectra emitted from the species ejected by excimer laser were systematically analyzed using optical emission spectroscopy and Boltzmann plot approach. These characteristics were correlated with the growth behavior of Pb0.95La0.05(Zr1−yTiy)0.9875O3films withy=1(PLT), ory=0.3(PLZT), synthesized by pulsed laser deposition technique. The increase in laser energy density moderately enhances the intensity of the spectral lines and insignificantly modifies the plasma temperature (Tp) of the Ti‐species in the plume. The increase in oxygen pressure PO2, on the other hand, only slightly reduces the intensity of the spectral lines but tremendously lowers the Tp‐values of the Ti‐species. The plasma temperature is around TPLZTp=20 300 K and TPLTp=12 500 K for PO2<0.01 mbar and abruptly decreases to around TPLZTp=13 300 K and TPLTp=8000 K for PO2=0.1 mbar or 1 mbar. High plasma temperature of the PLZT plume, as compared with that of the PLT plume, is presumably the source which induces the formation of secondary phase in the PLZT films. ©1995 American Institute of Physics.