The soldering joints of low silver solder and nano-particle composite solder were prepared by low-temperature soldering (at semi-solid state) with stirring. Researches have shown that the wettability and the filling ability of solders are improved by adding nano-Ni particles, the cavitary compounds of (CuxNi1-x) 6 Sn5 are generated by Ni with Cu6Sn5 and the micro voids formed by stirring at low temperature are the diffusion path of interface atoms, and the thickness of IMC increases compared with the soldering joints of low silver solder. The tensile strength and the shear strength is increased by 15.7% and 22.9%, respectively, and the low silver solder and its joints shift from the brittle broken to the ductile fracture after adding nano-particles. The tensile strength and the shear strength of the composites’ soldering joints are increased by 32% and 24%, respectively, compared with the soldering joints of low silver solder using stirring and flux, which is amount to or even better than the tensile strength and the shear strength of nano-particle composite solder