Abstract: The behavior characteristics of wire melting and fiber laser beam welding process of aluminum alloys with filler wire were carried out by using high-speed camera and experimental tests.The filler wire melting behavior and its main influencing factors were analyzed.The effect of wire feeding mode and wire feeding angle on weld formation and welding process stability were also studied.The results show that the melting behavior, which mainly depends on the distance between laser incident position and filler wire,can be divided into three types:the spreading transfer,the liquid bridge transfer and the globular transfer,and the liquid bridge transfer is the ideal type.The mode of pre-wire has higher efficiency and wider process window.The level of laser energy absorption by wire and the impact force of liquid wires on the liquid weld pool are affected by the wire feeding angle.The back weld width increases obviously with increase of wire feeding angle,while the weld penetration keeps essentially invariable.