The feasibility of laser direct welding quad flat pack (QFP) device without solder is analyzed and practiced. The relations between the tensile strength of QFP joints and laser welding parameters are investigated, and the optimized parameters are obtained. Further study of weld microstructure under the optimum parameters indicates the dependable metallurgical bonding has been formed. In accordance with the experimental parameters, the finite-element method is employed to simulate the temperature field of the welding process. The simulation results at optimum parameters of the welding spot's temperature distribution are discussed. The temperature rises linearly with the increment of loaded laser heating time, and the center temperature is rising much faster than other locations. The temperature is similar with actual measured highest temperature in this circumstance. It demonstrates the established model is satisfied, and the simulation result is reliable, which is significant to guide practical application.