[Purposes] This study aims to investigate the protective effects of planted concrete ecological slopes under the combined influence of earthquakes and rainfall. [Methods] Taking a planted concrete ecological slope on the Hechi-Du'an Expressway in Guangxi Zhuang Autonomous Region as the research object, this study utilized the 2-dimensional particle flow code (PFC2D) software for granular flow simulation. The advantages of analyzing large deformations and real-time tracking of cracks were leveraged. A numerical model of the planted concrete ecological slope was established using PFC2D, employing dynamic boundary conditions and the particle-flow-fluid-coupling principle to simulate seismic and rainfall conditions. The reinforcement effect of planted concrete on slopes under different conditions was investigated. [Findings] Under the sole action of earthquake, the slope with and without ecological slope protection has the phenomenon of cracks penetrating through the slope body. However, it is noteworthy that the former exhibited only small-scale unstable rock masses in the middle and bottom, while the latter formed large-scale unstable rock masses. Under the combined influence of earthquakes and rainfall, the former experienced shallow instability at the base, maintaining overall stability, whereas the latter exhibited local instability at the top, ultimately leading to overall instability. [Conclusions] Planted concrete ecological slopes effectively reduce the extent of slope damage under the combined influence of earthquakes and rainfall, preventing large-scale instability. However, localized fragmentation and sliding may occur at the base of the slope, necessitating reinforcement measures in this area.