[Purposes] Large-diameter monopiles are subjected to complex environmental loads, whose long-term cumulative deformation behavior critically influences the structural safety and service life of the overall system.This study provides theoretical support and an analytical framework for the design and long-term deformation prediction of monopile foundations.[Methods] This paper presents a series of 1g physical model tests on large-diameter monopiles embedded in saturated clay, with a focus on the pile cumulative deformation characteristics under various cyclic loading paths.[Findings] Test results demonstrate that under a constant average cyclic load amplitude, the accumulated pile-head displacement and rotation gradually decrease in the following order: one-way cyclic loading, two-way asymmetric cyclic loading, and two-way symmetric cyclic loading, indicating that one-way cyclic loading represents the most critical scenario. Based on experimental data, an explicit model for predicting the initial cumulative displacement at the pile head is developed, which incorporates both dynamic load level and cyclic loading path type.[Conclusions] Comparative analysis further reveals that the effect of loading path on cumulative deformation is more pronounced in sandy soils than in clay. Further investigation shows that α, effecting of the number of reaction cycles on the cumulative displacement of horizontal cycles, is not constant in clay but strongly correlated with the loading path parameter. Specifically, α increases gradually and eventually stabilizes as the loading condition transitions from two-way to one-way cyclic loading.