Ferroelectric is a great potential material in new solar cells and opto-sensitive field because of the anomalous photo-voltaic effect. Barium titanate is the most typical ferroelectric material. Optical properties of barium titanate have been extensively studied in order to use it as solar cells and optoelectronic sensitive materials. The research progress that the effect of sol-gel process, film thickness and doping of barium titanate thin films on the optical properties was reviewed, and problems were put forward in the furture.