BaTiO3 has become the key materials for the preparation of high-performance electro-optical modulators due to its high electro-optical coefficient, excellent piezoelectric properties and nonlinear optical properties. The quality, growth orientation and electro-optic coefficient of the film are determined by the preparation method, experimental condition and the selection of substrate, and further affecting the propagation loss, half-wave voltage and extinction ratio of the electro-optical modulator. Based on the working principle of electro-optical modulator, the factors affecting the orientation and quality of film forming were discussed by focusing on the preparation methods, experimental conditions and film substrates of BaTiO3 thin film in this paper. The advantages and disadvantages of each process of BaTiO3 thin film preparation were analyzed, the structure and performance of waveguide were discussed. Finally, the direction of optimizing BaTiO3 thin film fabrication and waveguide fabrication process in the future were summarized in this paper.