This study investigates the factors influencing micropore formation during the selective laser melting (SLM) process of 2219 aluminum alloy. A mesoscopic evolution model for SLM of 2219 aluminum alloy was developed using Ansys and other software, considering the temperature-dependent thermophysical properties of the alloy. The results showed that the temperature, surface tension and flow velocity of the molten pool under different process parameters would affect the formation of micropores during the scanning process, and the temperature difference would change the surface tension and further affect the flow velocity of the molten pool. The flow state of molten pool and the distribution of micropore morphology are also different. Adjusting the combination of laser power and scanning speed can produce a better effect on the mesoscopic micropore evolution of 2219 aluminum alloy. The study demonstrates the effectiveness of using Ansys-Fluent and its secondary development port to control the physical phenomena during the SLM scanning process, providing numerical simulation results of molten pool flow and monitoring the evolution of mesoscale micropores. This approach offers a theoretical basis for optimizing actual processing conditions.