Bi3.25La0.75Ti3O12 thin films with the thickness of about 365 nm were prepared on Pt/Ti/SiO2/Si substrates using the conventional metal organic decomposition method. The leakage current behaviour influenced by the soak time and the ultraviolet irradiation were studied. It was found that, on the one hand, when the testing voltage is below 2 V, the soak time has no significant effect on the leakage current. When the testing voltage increases to 5 V, the leakage current increases with the soak time increasing. On the other hand, the ultraviolet irradiation can change the leakage current of the thin films. When the testing voltage is above 4 V, with the illumination time increasing, the leakage current increases. The charge carriers participating in electric conduction were used to explain these experimental results (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)