Soldering technology for quad flat pack (QFP) devices is studied using a fiber laser based on scanning galvanometer with SnAg3.0Cu0.5 solder and the relationships between tensile strength of micro-joints and laser soldering parameters are obtained. Excellent lead-free solder joints are achieved at the laser soldering parameters of 11 W, 20 mm/s or 8 W, 10 mm/s. The speed of laser soldering is improved dramatically based on scanning galvanometers. The mechanical properties of micro-joints are compared for different soldering methods, including continuous-wave (CW) fiber laser soldering, pulsed fiber laser soldering and infrared reflow soldering. The results indicate that CW fiber laser soldering can obviously improve the tensile strength of the joints with SnAg3.0Cu0.5 solder. In addition, the tensile strengths of SnAg3.0Cu0.5 solder and Sn63Pb37 solder soldered by CW fiber laser are compared. The mechanical property of SnAg3.0Cu0.5 is observed to be outstanding. The microstructure of fracture surfaces indicates that the fracture mechanism is ductility fracture. The metallographic structure of the solder joints is also investigated. It is found that the structure of soldering seam is fine and the interface is flat. The generated intermetallic compounds layer is Cu6Sn5.