In recent years, the research of thin film LiNbO3 electro-optic modulator has developed rapidly, and its advantages such as small size, high bandwidth and low half-wave voltage have become the focus of attention. This paper reviews the research progress of waveguide structure, electrode structure and bias point control technology of LiNbO3 electro-optic modulator, analyzes the performances of three different waveguide structures, including planar mask, thin film ridge and photonic crystal, and discusses the characteristics and design considerations of two electrode structures of LiNbO3 modulator, namely, lumped and traveling wave. The advantages and disadvantages of bias point optical power control and disturbance signal control of electro-optic modulator and their related research results are summarized. Finally, the development trend of LiNbO3 electro-optic modulator is prospected.