The electrocaloric effect of 9/65/35 PLZT thin film fabricated by the sol-gel method, which has not been studied yet, was investigated for its structural, electrical properties as well as temperature change property. The relaxor ferroelectric property of 9/65/35 PLZT thin film was confirmed by examining its dielectric and electrical properties. The relaxor property can cause a more pronounced electrocaloric effect (ECE) in a wider temperature range than normal ferroelectric film. To avoid errors caused by using an indirect measurement method, the leakage current generated by increasing temperatures was minimized by using the optimal maximum electric field ($350kVcm^{-1}$) in the thin film. The largest temperature change ${delta}T$ (0.23 K) and the electrocaloric strength ${xi}$ (0.68 mkcm/kV), calculated by equations were obtained. The maximum field change ${delta}E$ ($191kVcm^{-1}$) was in the vicinity of the curie temperature ($200^{circ}C$).