Compared with the traditional addition methods of lumpy lime into the electric arc furnace (EAF) for slag making, the technology of O-2-CaO jet can deliver lime powder directly into the EAF molten bath with high speed carrier gas, which demonstrates much advantages in quick melting and effective phosphorus removal. Recently, the shrouding combustion flame was proposed and applied to strengthen the CaO import capability of the O-2-CaO jet. In this study, combining the discrete particle model (DPM) and the Eddy Dissipation Concept (EDC) model with the detailed chemical kinetic mechanisms (GRI-Mech 3.0), computational fluid dynamics (CFD) models of the O-2-CaO jet with shrouding flame, with shrouding O-2 and without shrouding gas were developed. The numerical results of CFD models were firstly validated by the experimental data. The interaction between the particles and the gas jet of the O-2-CaO jet was analyzed and how the shrouding combustion flame affected the fluid flow characteristics of the O-2-CaO jet were clarified. The shrouding high-temperature combustion flame could delay the attenuation of the axial velocity of the O-2-CaO jet, heat the CaO particles effectively and make the CaO particles cluster together in a much longer distance, which is helpful to strengthen the jet impact, accelerate the meltdown of CaO particles and improve the utilization efficiency of CaO.