In this paper, a full scale cold model of 500 t/d entrained-flow gasifier by two-stage oxygen was used to analyze the distribution characteristics of the aerodynamic field in the gasifier. The realizable k-epsilon turbulent model was adopted to simulate the three-dimensional turbulent flow field with the SIMPLE (semi-implicit method for pressure-linked equations) algorithm for the gasifier. The effects of side injecting velocity, position, number of nozzles, and group mode on aerodynamic field distributions were analyzed. The results show that the numerical simulation data are well-matched with the experiment data. The simulated results are acceptable and can present a foundation for the future design, assessment, and further optimization of the entrained-flow gasifier by two-stage oxygen.