During laser direct energy deposition, the temperature distribution and flow state of the molten pool directly impact the quality of the deposited layer. Analyzing the dynamic behavior of the molten pool helps improve our understanding regarding the mechanism of molten pool formation, thereby reducing the occurrence of defects. This study established a coupled simulation model of the temperature and flow fields during laser direct energy deposition. The model considered the Marangoni effect and employed a dynamic mesh method to simulate molten pool morphology. Furthermore, this study investigated how different process parameters affect the temperature field and flow rate of the molten pool during single-pass single-layer deposition and the variations in the temperature field and morphology during the overlapping of multiple passes owing to asymmetric heat transfer. Results indicate that laser power, scanning speed, and powder feeding rate considerably affect the temperature field and flow rate of the molten pool, with laser power exhibiting the most substantial influence. Asymmetric heat transfer causes the temperature of different melt tracks to increase and then stabilize, leading to a consistent growth trend in the molten pool depth.