Random fiber network materials are ubiquitous in biological and artificial materials and extensively utilized in filtration and absorption, thermal insulation and shock absorption, chemical catalysis, tissue engineering, flexible electronics and aerospace because of their low density, high porosity, large specific surface area, strong deformation ability, excellent specific performances and controllable structures. However, when compared to traditional homogeneous continuous materials, the intricate microstructure of random fiber networks poses significant challenges in studying their mechanical properties. This article provides an extensive review of the research progress made on random fiber networks from two focal points: microstructure characterization and evaluation of mechanical performance. It summarizes the key accomplishments and unresolved issues, encompassing experimental testing, establishment of constitutive relationships, and numerical simulations pertaining to these materials. Additionally, the contribution emphasizes the emerging trends in the research of mechanical performance for random fiber networks.