The Pearl River Delta (PRD) urban agglomeration is an important part of the Guangdong-Hong Kong-Macao Greater Bay. It is of great significance to study the ecological security and spatial pattern of the PRD urban agglomeration under the background of the national policy of implementing the construction of the Guangdong-Hong Kong-Macao Greater Bay. The ecological security evaluation system of urban agglomeration was constructed in the PRD based on the PSR conceptual model

and the set pair analysis and spatial autocorrelation analysis methods were applied to analyze the spatial heterogeneity and aggregation characteristics of urban agglomeration ecological security. The results show that the PRD is affected by urbanization

and the ecological security level shows an obvious spatial differentiation. The ecological security level of the central area

where it highly urbanized

is significantly lower than that of the peripheral area. The peripheral area forms an ecological barrier to the central area. The level of ecological security has a significant relationship with regional economic development

and the level of ecological security and economic development are negatively correlated in space. The clustering of ecological security in cities shows a “low-high” or “high-low” agglomeration situation. Cities with higher ecological security tend to be adjacent to cities with lower ecological security

showing a complementary spatial pattern. This spatial differentiation and aggregation characteristics have important guiding significance for the future ecological planning

urban ecological construction and ecological management of the urban agglomerations of the PRD and Guangdong-Hong Kong-Macao Greater Bay.