Abstract: Beach cusps are typical rhythmic landforms located on beaches, and their formation and evolution mechanisms are important topics in coastal dynamic geomorphology. This study takes the central beach of Donghai Island in western Guangdong as a typical study area. Based on UAV aerial survey technology, short-term comparative image data were obtained, and high-precision digital surface models were generated using visible-light imagery. Morphological parameters, including beach cusp spacing, depth, and height, were extracted using the contour method, and Pearson correlation analysis was applied to systematically analyze the short-term evolution characteristics of beach cusp morphology during the monitoring period. The results show that: (1) During the monitoring period, the beach cusp morphology exhibited a significant trend toward homogenization: the number of cusps increased (from 25 to 48), their spatial distribution became more regular, spacing remained stable, while the mean depth and height decreased, with an overall reduction in the dispersion of parameters; (2) Under the influence of stable moderate swells (wave height 0.6–0.9 m, E and ENE directions), the correlations among morphological parameters decreased significantly, and the spacing–height relationship became completely decoupled, revealing that the beach cusp system was in a phase of morphological construction and adjustment dominated by positive feedback within the self-organization process during this short-term monitoring period; (3) Significant deviations were observed between the measured values and the predicted values of edge wave theory, suggesting that the explanatory power of edge wave theory for beach cusp formation in the study area is limited under the hydrodynamic conditions and timescale of this monitoring period. This study demonstrates the applicability and reliability of UAV aerial survey technology for extracting and monitoring the morphological characteristics of beach cusps, providing a high-resolution empirical case for understanding the short-term evolution processes of coastal landforms.