Fossil has great scientific value because it has witnessed geological history, climatic change, biological evolution, etc. The diagenetic process, combined with chemical, physical, and biological interactions, leads to fossils having higher resistance to weathering and can be stored stably by development and consolidation. However, the composition of some fossils could easily undergo chemical and physical changes in a relatively humid environment, leading to the development of cracks, spalls, and powder, which threatens the conservation of fossils. This paper briefly reviews the development of fossil conservation and focuses on the mechanism and conservation management of fossil weathering, such as salt decay, pyrite decay, and cracking by losing water. Finally, we briefly discuss the relationship between the conservation of fossils and cultural relics. The aim of this review is to guide readers in managing weathering fossils and promote fossil conservation for further development.