Due to it is irreplaceable physical characteristics, Hollow core optical fiber has become a precious basic research topic for scientific research institutions. However, the industry has been keeping a wait-and-see attitude because of its overall performance and supporting applications are not mature. In recent years, with the continuous optimization of the loss performance, and the successful promotion of several industrial application cases, hollow core fiber has gradually been paid more attention by the industry side. In this paper, three types of hollow core fibers: hollow core bragg layered fiber, hollow core photonic bandgap fiber and hollow core antiresonant fiber, are reviewed. The paper is mainly focused on their optical principles and testing methods, and combined with the application of communication, laser power delivery and sensing fields to analyze the advantages of hollow core fiber. Finally, the future technology development trend of hollow core fiber is prospected.