MCs are produced by cyanobacteria and cause concerns in potable water due to toxicity. Conventional treatments are poor at removing MCs. In the present study, the photocatalytic degradation of MC-LR was conducted using nano-TiO2 thin film, prepared by sol-gel and dip-coating method, with UV 365nm irradiation. According to analysis results from solid-phase extraction combined with HPLC method, the trace-level MC-LR is easily to be removed by photocatalytic system. The degradation efficiency of MC-LR is influenced by the pH conditions, initial concentration due to adsorption of MC-LR on TiO2 thin film. The maximum initial rate of photocatalytic degradation occurs at pH 4 and over 95% of 20μg/L MC-LR is decomposed within 120min. The kinetic equations and parameters revealed that degradation reaction of trace level MC-LR, which depicted by pseudo first order kinetics process in appearance, was in accordance with Langmuir-Hinshelwood kinetics model well, the corresponding rate constant k and Langmuir adsorption constant K were determined to be 19.72μg/l·min-1 and 6.57×10-4l/μg, respectively.