In recent years, photonic chips have emerged as a significant direction in the development of photonics due to their characteristics of large-scale integration, low cost, low power consumption, and fast response. Lithium niobate is considered as a promising material for photonic chips because of its large second-order nonlinear coefficient, strong electro-optic effect, and other properties. A crucial challenge for the application of lithium niobate photonic chips is the interface between optical fibers and photonic chips. Grating couplers have become an important solution to the fiber-to-chip coupling problem due to their high flexibility, large misalignment tolerance, and ease of fabrication. This paper reviews recent research progress on thin-film lithium niobate grating couplers, summarizes several approaches to enhance their performance, and provides perspectives on their future development.