Myopia is the most common ametropia. High myopia, especially pathological high myopia, is often accompanied by a series of fundus pathological changes, such as Fuchs spot and choroidal neovascularization(CNV), etc, which can lead to serious damage of visual function. In recent years, it has been found that the changes of choroidal thickness and blood flow play a considerable role in the progression of high myopia. The change of choroidal thickness can directly reflect the abnormality of its structure and function. The choroidal thickness in high myopia is significantly thinner than that in normal people, and the thinning degree varies in different regions. At the same time, the choroid is the main source of blood supply to the eyes, and its blood flow directly determines whether the blood supply is sufficient to the eyes. Therefore, observing the changes of choroidal thickness and blood flow in high myopia is of great significance to explore the progress of myopia or observe its pathological changes. This review illustrates the choroidal structure, thickness and choroidal blood flow changes of high myopia. At the same time, it analyzes and discusses the new research progress and main existing problems in recent years, the new challenges and future research directions, hoping to provide help for clinical monitoring of the occurrence and progression in high myopia.