Crystal fiber is a new type of high performance fiber material with high concentration of rare earth ions, good light transmission, high temperature resistance and corrosion resistance. It has been recognized that crystal fiber has great potential in laser and sensing applications. However, small core diameter crystal fibers with crystalline core and crystalline cladding have not been successfully fabricated. Compared with traditional glass fiber, the preparation process of crystal fiber is more complicated. How to improve and innovate the crystal fiber preparation process is an important problem that needs to be solved. In order to explore ways to improve the quality of crystal fiber, this paper takes the four preparation techniques of crystal fiber as the main line, reviews the development history of crystal fiber and its preparation method, discusses the limitations of each preparation method. The current application status of crystal fiber is summarized and its development trend is prospected.