Abstract: In order to investigate the influence of the mesoscale porous structure of sintered silver nanoparticles on the macroscale mechanical properties, representative volume elements (RVEs) with different porosities (0.1, 0.2 and 0.3) are firstly generated by using the Gaussian filtering algorithm and the cutting quantile functions. The uniaxially tensile mechanical properties of the RVEs are obtained by applying periodic boundary conditions. A macroscale model of the lap joint made of sintered silver nanoparticles is then established using Abaqus software to simulate the shear test. The material properties of the sintered layer are consistent with the predicted elastoplastic stress–strain curves of the RVE. The findings reveal that as the porosity decreases, the elastic modulus and yield strength of the RVE model increase. However, it is worth noting that the stress at the final stage of the plastic deformation demonstrates a significant decreasing trend as strain increases, rendering the material more susceptible to damage. Furthermore, through a comparison of shear simulation results of the macroscale model, it can be observed that porosity variations have a notable impact on the shear deformation of sintered silver nanoparticles. Specifically, as the porosity increases, the likelihood of crack initiation and propagation in porous regions rises. This leads to the coalescence of cracks among multiple pores, consequently resulting in the reduction of shear strength of the sintered silver nanoparticles.