在构建新发展格局与突破“卡脖子”技术的战略背景下，“专精特新”政策作为培育科技“小巨人”企业的重要举措，为我国高科技产业创新驱动发展战略提供了可行方案。本文以1998—2022年中国A股上市公司为样本，通过多期双重差分法系统考察“专精特新”政策对企业全要素生产率的影响及其作用机制。研究发现:“专精特新”政策可以显著提升企业全要素生产率，在剔除内生性问题后结论仍然成立。拓展研究发现，“专精特新”政策对企业生产率的影响兼具集约边际与拓展边际双重效应。异质性分析显示，政策效果集中于工业部门，印证该政策对《中国制造2025》重点领域的靶向支持。机制分析表明，“专精特新”政策通过“挤入”民间研发投资和延伸供应链两条路径提升企业的生产率。本研究验证了“专精特新”政策对科技“小巨人”企业成长的积极影响，为优化产业政策设计、强化供应链韧性提供了理论依据与经验证据。

Under the strategic background of constructing a new development paradigm and breaking through "bottleneck" technologies，the "specialized，refined，distinctive and innovative" （SRDI） policy，as a crucial measure to cultivate technology-based small giant enterprises，urgently requires scientific evaluation of its policy effects. Using a sample of Chinese listed companies from 1998 to 2022，this study systematically examined the impact of the SRDI policy on firms' total factor productivity （TFP） and its mechanisms through a multi-period difference-in-differences approach. The findings revealed that the SRDI policy significantly enhances enterprise TFP，with results remaining robust after addressing endogeneity concerns. Extended analyses demonstrated that the policy exerts dual effects on productivity growth—simultaneously operating through intensive margin （efficiency improvements） and extensive margin （scale expansion） channels. Heterogeneity analysis indicated concentrated policy effects within the industrial sector，validating its targeted support for key domains outlined in the Made in China 2025 strategy. Mechanism tests identified two transmission pathways:（1） crowding-in private R&D investment，and （2） extending supply chain linkages. This research empirically verifies the SRDI policy's positive role in fostering the growth of niche technology leaders，and will provide theoretical underpinnings and empirical evidence for optimizing industrial policy design and strengthening supply chain resilience.