Rapid thermal annealing (RTA), conventional furnace annealing (CFA) and combined RTA and CFA annealing (RCA) were adopted for thermal treatment of lead lanthanum titanate (PLT) thin films. Through comparison of morphologies, dielectric and ferroelectric properties, current-voltage (I–V) and capacitance-voltage (C–V) characteristics as well as pyroelectric currents, the features of each thermal annealing process were discussed. Optimized thermal annealing process was proposed. PLT thin films prepared by RCA process have higher remanent polarization, flatI–Vcurve, sharper nonlinearity peaks ofC–Vcurve and larger pyroelectric current density.