Addressing the well leakage issues encountered during drilling in volcanic clastic rock formations, this paper thoroughly analyzes the causes of well wall instability and frequent loss, and explores the possibility of improving plugging efficiency and well wall stability through scientifically formulated plugging materials (lost circulation materials, LCMs). Focusing on the common problems of plugging materials in such complex formations—such as poor adaptability to the leakage layer, inadequate temperature resistance, and insufficient pressure-bearing capacity, the paper introduces a new scientific plugging strategy aimed at increasing the success rate of plugging and improving the replicability of plugging methods. The study employs experimental and numerical simulation methods to optimize and evaluate different formulas of plugging materials for their leakage resistance and borehole wall stabilization in the drilling fluid system. The research results show that a carefully designed combination of rigid and flexible materials can achieve better plugging results in performance tests for fractures of various widths, with formulas one and four performing particularly well. Therefore, choosing the appropriate plugging material formulation plays a significant role in enhancing the success rate of a single plugging attempt and well wall stability, which is crucial for ensuring drilling safety and progress.