ABSTRACT The hysteretic working capacity of reinforced masonry shear (RMS) walls has been estimated empirically and statistically referring to the structural ultimate state with considerable uncertainty. This investigation is to try to break this puzzlement of the uncertainty by revealing the hysteretic working features of RMS walls applying structural state-of-stress theory. The experimental residual strains are firstly modeled as generalized strain energy density (GSED) values (state variables) to describe structural state-of-stress mode and its characteristic parameter (GSED sum). Then, the slope increment criterion is proposed to detect the state-of-stress mutation point in the GSED sum-load curve. Accordingly, it is verified that the evolution of the state-of-stress mode presents the mutation feature. Thus, the starting point of the RMS wall’s failure process is revealed as the embodiment of the natural law from quantitative change to qualitative change of a system. And the hysteretic failure load of the RMS wall is defined at the state-of-stress mutation point with the attribute of certainty and generality. Furthermore, the GSED-based analysis reveals the working features between the state-of-stress submodes of structural components. This investigation explores a new way to analyze the hysteretic working behavior of RMS walls, which provides the rational reference to the accurate estimation of the failure loads of RMS walls for designs.