With the discovery of graphene, people have discovered that two-dimensional materials have unique properties and significance. Therefore, two-dimensional material-based photodetectors are also very valuable for research. This article first discusses the excellent properties of photodetectors based on two-dimensional materials, including high sensitivity, high modulation frequency, and wide spectral response capability. Then, recent research results on two-dimensional SnSe2/GaP type-II heterostructure photodetectors and photodetectors utilizing two-dimensional WSe2 were introduced. Additional representative studies, including two-dimensional layered materials-based valanche photodetectors and two-dimensional tin (II) sulfide (SnS) nanoflakes-based photodetectors, were also shown. The prospects and challenges of photodetectors based on two-dimensional materials were also discussed at the end of the article. They can be applied in fields such as video imaging, gas sensing, biological imaging, safety, night vision, optical communication, and motion detection. The issues of device stability, mass production, cost, and uniformity need to be addressed and find their more ideal commercial applications.