The plate-monopile hybrid foundation is an innovative solution developed to support increasingly larger offshore wind turbines under harsher marine conditions. However, due to its structural differences from monopile, the bearing capacity estimation model and failure mechanisms remain unclear. In this study, FEM simulations were performed to obtain the bearing capacity of the hybrid foundation for various soil parameters and foundation geometries, covering representative worldwide seabed conditions as well as current and future design parameters in the offshore wind industry. The failure envelopes of the hybrid foundation under different parameter combinations were established, and the empirical formulas for estimating the ultimate bearing capacity were derived based on extensive simulation results. The results indicated that (1) Both lateral load bearing capacity (H_R) and moment bearing capacity (M_R) were positively correlated with soil properties and foundation geometry, with consistent parameter effects. (2) The failure envelope of the hybrid foundation in the -plane exhibited an elliptical shape, and variations in different parameters affected the curvature of the envelope to distinct extents. (3) The applicability of the proposed bearing capacity prediction formula for the hybrid foundation incorporates both soil properties and foundation geometric parameters was quantitatively validated against previous research cases.