Abstract: The long-term creep performance of carbon fiber reinforced polymer (CFRP) tendon composite anchorages critically affects the structural safety and service life of bridges, serving as a key limitation to their widespread application in long-span bridges. To investigate the creep behavior of a novel mechanical-bond composite anchorage under hygro-thermo-mechanical coupling conditions, a refined three-dimensional finite element model (FEM) was developed based on experimentally determined hygrothermal degradation and creep characteristic parameters of epoxy resin (ER). The validity and accuracy of the FEM were validated against the hygrothermal creep test data of anchorages. Results demonstrate good agreement between numerical simulations and experimental data, indicating that the FEM can accurately simulate the creep behavior of the composite anchorage under various hygrothermal conditions. Parametric analysis reveals that the anchorage creep slippage decreases with the increase of anchorage length. Moreover, the creep slippage of the anchorage increases significantly with higher immersion temperatures or increased load levels. The incorporation of 0.5?vol% basalt fiber powder into the ER notably reduced anchorage creep slippage compared with that of the anchorage with pure ER, achieving a reduction of up to 36.9%.