This study focuses on the seismic performance assessment of slopes reinforced with pile anchor structures. Pile anchors are a common and effective method for stabilizing slopes, especially in areas with weak or unstable soil. However, the dynamic behaviour of pile anchor structures in slope reinforcement is yet to be explored. To address this gap, the study presents a fragility analysis approach based on incremental dynamic analysis to evaluate the factors of safety and permanent displacement of pile anchor structures under seismic loading. The performance-based earthquake engineering analysis involves conducting a series of dynamic time history analyses using multiple seismic records of varying scales. By considering different vulnerability states, fragility functions are developed to assess the performance of pile anchor structures in terms of factors of safety and permanent displacement. The analysis incorporates various factors such as soil strength, stiffness, slope geometry, anchor structure characteristics, and dynamic forces during earthquakes. The obtained fragility functions provide valuable information regarding the failure probabilities of pile anchor structures under different vulnerability states, thereby aiding in the design and evaluation of slope reinforcement measures for enhanced seismic resilience.