Abstract: Engineering cementitious composites (ECC) has gained widespread application in engineering structures due to their superior mechanical properties. ECC jackets are commonly employed in the plastic hinge regions of columns to enhance deformation resistance. Existing research lacks a systematic mechanical model for ECC jacketed composite columns and an analysis of influencing factors. This study divided the compression zone of ECC jacketed composite column sections into distinct regions and established strength and displacement calculation models for the three types of ECC jacketed composite columns. These models incorporated ECC constitutive relation curves that account for residual strength degradation, for the restraint effect of the ECC jacket, for the impact of the ECC jacket on the cyclic strength reduction coefficient of longitudinal reinforcement and, for assumptions regarding ordinary concrete edge strain. The accuracy of these models was validated through experimental testing. Numerical simulations analyzed the influence of different ECC jacket heights, introducing a proportional reduction factor based on the 45° angle stress diffusion theory, and the effects of ECC material strength and axial compression ratio were comprehensively evaluated. The tripartite skeleton curve model was refined, proposing a functional skeleton curve model that considered the bearing capacity changes of column specimens, providing a more accurate characterization of column behavior. The research results have certain reference significances for the subsequent engineering application and research of ECC jackets.