Abstract: In the context of ongoing global sea level rise, the response mechanisms of beaches along fixed coastlines have become a critical issue in coastal evolution studies. The classical Bruun rule, based on the equilibrium profile assumption, suggests that natural beaches can adapt to sea level rise by shifting landward. Under the case of widespread presence of rigid structures such as seawalls, however, the space for shoreline retreat is limited and whether the adjustment process of beach dynamical geomorphology has undergone changes remains significant controversy. Some studies argue that seawalls can intensify passive erosion by enhancing wave reflection and localized scouring, whereas others indicate that, under specific hydrodynamic and sediment supply conditions, seawalls may induce localized accretion or lead to the formation of new dynamic equilibrium. In response to these divergent views, the driving mechanisms of sea level rise, the seawall space types and differences in their relative positions and the hydrodynamic–sediment coupling processes in front of the seawall as well as the applicability and limitations of predictive approaches such as the Profile Translation Model (PTM) are overviewed systematically. The results indicate that the seawalls can make the beach responses exhibit significant scenario-dependent and regional variations by constraining landward profile translation, redistributing sediment budgets and intensifying nearshore erosion. In the future, it is necessary to strengthen the accumulation of long-term measurement data, to integrate numerical modeling with scenario analysis and to develop a comprehensive evaluation framework suitable for fixed shoreline conditions, thus providing a scientific basis for optimizing coastal protection and making decisions on beach conservation.