Lithium iron phosphate (LiFePO4) thin film electrodes were prepared by pulsed laser deposition (PLD). The thin films were annealed at various temperatures under argon gas flow and the influence of annealing temperature on their electrochemical performance was studied. The thin films annealed at 773 and 873K exhibited a couple of redox peaks at 3.4V (versus Li/Li+) that are characteristics of the electrochemical lithium insertion/extraction of LiFePO4. Atomic force microscopy (AFM) observation revealed that the film annealed at 773K (773K-film) consisted of small grains with 50nm in thickness, and the grain size increased with an increase of annealing temperature. Because of its small-sized grains, the 773K-film showed high rate capability and the discharge capacity at 10μA maintained 65% of that at 25nA. However, the discharge capacity of the 773K-film was ca. 10% smaller than that of the film annealed at 873K, indicating that annealing at 773K is slightly insufficient to obtain well-crystallized LiFePO4. From these results, it was concluded that a point of optimization between high rate capability and capacity would be found between 773 and 873K.