Abstract: Soldering technology for quad flat pack devices(QFP) were studied by means of 90W diode-laser soldering system and the mechanical properties of micro-joints of QFP were compared with different laser power.Results indicate that diode-laser soldering can obviously improve both the tensile strength of the joints with Sn-Ag-Cu solder and the strength of the joints with Sn-Pb solder.The diodelaser output power directly influences the tensile strength of the micro-joints of QFP with the same solders.These results will provide a good method for improving the strength and reliability of fine pitch QFP devices.