Sintered silver nanoparticles (AgNPs) are widely used in the electronic packaging of high-power chips, yet their random internal porous structure is prone to fatigue degradation. In this study, a new cyclic cohesive zone model (CCZM) is proposed for predicting the fatigue lifetime of sintered AgNPs. This model not only considers the cumulative effect of damage slip during cyclic loading but also realizes simultaneous stiffness and strength fatigue degradation under low-stress loading. In addition, to improve the usability of the model, a low-cost estimation method of the model’s key parameters and the corresponding VUMAT user subroutines are proposed. Based on this, cyclic tensile tests on Sintered specimens confirm the occurrence of damage slip within the porous AgNPs structure. The predictive performance of the model and the sensitivity of its characteristic parameters are also thoroughly analyzed and discussed. The new CCZM provides a solution that balances modeling complexity and engineering convenience for the reliability assessment of porous structures.