To improve the desulfurization efficiency of hot metal with mechanical stirring, the distribution and motion behavior of desulfurizer particles have been investigated by numerical simulation. The volume fraction of desulfurizer particles in different ladle regions and particle trajectory are further discussed. In addition, the effects of rotation speed and eccentricity of impeller have also been elucidated. The results show that the motion of desulfurizer particles in different ladle regions takes about 10s to reach a dynamic steady state. The particle volume fraction in upper circulation region (56.2%) is about 2.0 times that in middle agitation region (27.7%), and about 3.5 times that in lower circulation region (16.1%). The typical motion trajectories of desulfurizer particles can be summarized into four types. The largest particle volume fraction in upper circulation region is mainly attributed to the first and fourth types of motion trajectories, while the second and third types of trajectories contribute to the particle volume fraction in middle agitation region and lower circulation region respectively. The greater rotational speed is more conducive to desulfurization, however the rotation speed is not recommended to be >90 rpm to avoid the possibility of overflow during actual production process. Compared with the centric stirring, the impeller eccentricity of 100 mm is recommended and more beneficial to desulfurization.