This study proposed a steel rocking column base that dissipates seismic energy through a pair of replaceable steel cover plates. Three specimens of the proposed steel column base were designed and tested under static cyclic loading. Hysteretic response, failure modes, and energy dissipation of the column base were obtained and discussed. Then three-dimensional finite element model of the column base was built and validated against the test results. Later on, a component method was employed to predict the rotational stiffness and capacity of the column base. The Yield Line Theory was employed to predict the ultimate capacity of the cover plates and the demand of axial resistance of anchoring rods. It shows that the proposed column base is capable of dissipating seismic energy through the plastic bending of the cover plates. The moment resisting capacity increased with the increasing yield strength and thickness of cover plates and axial compression ratio, wherein the axial compression ratio has the most significant effect. The proposed design equations can predict the rotational stiffness of the column base and ultimate capacity of the column base with acceptable accuracy. Moreover, stiffening approaches for the column end were also presented to facilitate the practical design of the proposed column base.