In order to gain a better understanding of deoxidation phenomena, there is a need to develop a model that could involve mass transfer, nucleating and growth kinetics of inclusion to simulate unhomogeneous state at the initial stage of Al deoxidation process. Based on the computation of the model for steel droplet with aluminum at center, it is found that the reaction zone between aluminum and oxygen in liquid steel is located in a limited zone at a certain fixed time and it is moved from center to outmost with the time going. For the zone besides the deoxidizer, i.e. aluminum, the supersaturation degree S_O is very high at first, and then is decreased quickly, and the main part of oxygen in steel is absorbed by nucleation. In the other side, for the outmost zone, the main part of oxygen in steel is absorbed by growth of inclusion and the growth of inclusion lasts for longer time than that of inner zones.