Stricter specifications have been set on the characteristics of Sn-Zn-Cu-Ni lead-free solders due to the advancement of microelectronic packaging and the growing need for solder joints to have specialized service environments. Therefore, nanoparticles have been widely used to enhance the properties of such solders. This study aimed to investigate the effect of TiO2 and ZrO2 nanoparticles on characterizations for Sn-6.5Zn-0.5Cu-0.2Ni lead-free solder. Thermal properties such as the melting temperature, solidus, and liquidus temperatures, as well as the pasty range and heat of fusion of Sn-Zn-Cu-Ni, Sn-Zn-Cu-Ni-TiO2, and Sn-Zn-Cu-Ni-ZrO2 solders, were investigated by the Differential Temperature Analysis (DTA) technique. Also, the electrical resistivity, electrical conductivity, thermal conductivity, and the temperature coefficient of resistance were measured at different testing temperatures. From microstructure analysis, the lattice parameters, unit cell volume, and crystal size of the β-Sn matrix are improved by adding TiO2 or ZrO2 nanoparticles. Also, the grain size of the β-Sn is decreased with a uniform distribution of intermetallic compounds upon adding TiO2 or ZrO2 nanoparticles. The internal friction, thermal diffusivity, and Young’s modulus were enhanced with the addition of TiO2 or ZrO2 nanoparticles, and the best effect is for ZrO2 nanoparticles.