Casting speed, casting temperature and secondary cooling water flow rate are the main process parameters affecting the DC casting process. These parameters significantly influence the flow and temperature fields during casting, which are crucial for the quality of the ingot and can determine the success or failure of the casting operation. Numerical simulation, with the advantages of low cost, rapid execution, and visualized results, is an important method to study and optimize the DC casting process. In the present work, a simulation model of DC casting 2024 aluminum alloy was established, and the reliability of the model was verified. Then, the influence of casting parameters on flow field and temperature field was studied in detail by numerical simulation method. Results show that with the increase of casting speed, the melt flow becomes faster, the depths of slurry zone and mushy zone increase, and the variation of slurry zone depth is greater than that of mushy zone. With an increase in casting temperature, the melt flow rate increases, the depth of the slurry zone becomes shallower, and the depth of the mushy zone experiences only minor changes. The simulation results further indicate that the increase of the flow rate of the secondary cooling water slightly reduces the depths of both slurry and mushy zone.