Water splitting with proton exchange membrane water electrolyzers (PEMWE) is regarded as a promising pathway for sustainable hydrogen conversion. Additionally, oxygen evolution reaction (OER) is considered as the dominant factor during the whole process due to the sluggish kinetics. Among the catalysts, Ru-based catalysts draw special attention because of their excellent activity and relatively low price. However, the limited stability impedes their further commercialization and tremendous efforts have been devoted to overcome this challenge. This review firstly introduces the basic mechanisms of OER. Then the evaluation protocols and techniques to investigate the stability of Ru-based catalysts are summarized. A detailed elucidation of the possible degradation mechanisms is also critically analyzed. Furthermore, effective strategies to design durable Ru-based catalysts for acidic OER are discussed. Such as heteroatom doping, phase and facet engineering, heterostructure building and support optimization. Finally, promises, perspectives and challenges in developing highly durable Ru-based catalysts for acidic OER are outlined.