Abstract: Miniature Lead-Cooled Fast Reactors (LFRs) pose a substantial challenge to traditional reactivity control methods due to their compact core size and high neutron leakage environment, which render traditional insertable control rods ineffective. This study introduces the design and evaluation of a novel reactivity control strategy, coupled with a systematic source term analysis post-shutdown, to ensure operational safety and provide a robust foundation for future engineering. We propose an innovative, multi-layered redundant control strategy that includes active control drums (for regulation and safety) and passive safety blocks. This approach uniquely integrates ex-core control drums for fine-tuned, low-perturbation reactivity management and shutdown, with buoyancy-driven passive safety blocks serving as the ultimate defense-in-depth mechanism. The reactivity worth of this system was accurately modeled in three dimensions using a Monte Carlo code, while the source term evolution over a ten-year post-shutdown period was calculated for zoned fuel assemblies using the ORIGEN2 code, ensuring physical consistency. The results indicate that the proposed control strategy maintains an ample shutdown margin, achieving a deep subcritical state through the synergistic operation of all control drums, even under the most conservative accident scenarios. Moreover, the passive safety blocks guarantee a shutdown in the event of an active system failure, significantly enhancing the reactor's inherent safety. The source term analysis identifies the primary contributing nuclides at various cooling stages and provides essential data on zonal component activity, decay heat, and neutron and gamma source strengths. In conclusion, the innovative control strategy developed in this study enables effective and reliable reactivity control and safe shutdown for miniature LFRs. Furthermore, this work characterizes the spent fuel source term in detail, accurately identifying key contributing nuclides across various cooling stages and energy intervals. These findings provide a crucial physical basis and comprehensive data support for shielding design, spent fuel management, and safety evaluation.