Lanthanum-doped lead zirconate stannate titanate antiferroelectric thin films were deposited onto Pt-buffered silicon substrates using the pulsed laser deposition method. The deposition temperature was 570°C. The postdeposition annealing process was carried out in an oxygen-flow tube furnace at temperatures ranging from 650 to 800°C for a duration of 30 min; its effects were studied through the variations of the microstructure as well as the electrical and dielectric properties. It was found that an appropriate annealing process at temperatures above 700°C could substantially improve the dielectric properties. However, annealing beyond 800°C caused the film properties to deteriorate severely. Explanations were given with regard to the microstructure-property relationship.