Weldability of magnesium alloy to aluminum alloy in laser weld bonded (LWB) joints are investigated. Results showed that magnesium/aluminum could be easily joined by LWB under proper technological parameters. The weld is characterized by complex vortex flow at the bottom and there existed intermetallic compound layer between weld pool and lower sheet metal which was composed of the brittle phases of Al3Mg2. The aim of this research is to evaluate the weldability using LWD process to join Mg/Al alloys using HLD 3504 – Laser Type Trumpf, to explain the experimental conditions and interpretation of results.