This paper presents a multi-laser beam focusing on laser welding based on a reflective splitting mirror, aiming to improve the stability of the laser welding process and reduce welding defects. By validating the laser welding process on Q235 mild steel using a newly developed multi-focused laser beam, the results show that by increasing the number of laser focal points, the porosity and spattering are effectively reduced, thus achieving higher process stability. Additionally, the rotation of the laser focal point further reduces the occurrence of welding defects such as porosity and spattering.