科技企业进入是经济实现高质量发展的创新引擎。本文基于2004—2018年283个地级市与工商企业注册信息匹配数据，以长三角城市经济协调会的成立为准自然实验，运用机器学习法识别统一大市场建设对科技企业进入的影响。结果显示：统一大市场建设显著促进了科技企业进入数量的增长和规模的提升，且上述促进作用在城市规模小、融资约束高以及政府创新扶持弱的样本中更为显著。机制分析表明，统一大市场建设通过人才集聚效应、技术集聚效应和风险投资集聚效应促进科技企业进入。进一步研究发现，相较于中心城市，统一大市场建设对外围城市的科技企业进入数量和规模存在更为强劲的促进作用，因此有助于促进区域均衡发展。本研究的结论不仅为理解统一大市场建设的经济效应提供了新的视角，也为全国统一大市场的深入推进和区域均衡发展的政策制定提供了参考建议。

The entry of technology enterprises serves as the innovation engine for achieving high-quality economic development. Utilizing a dataset that matches the registration information of industrial and commercial enterprises with 283 prefecture-level cities from 2004 to 2018，this paper adopted the establishment of the Yangtze River Delta Urban Economic Coordination Committee as a quasi-natural experiment，and used the machine learning method to identify the impact of unified market construction on the entry of technology enterprises. The results showed that the construction of a unified market significantly stimulates the increase in the number of technology enterprises and the enhancement of their scale，and the above promotion effect is particularly pronounced in samples characterized by smaller city size，higher financial constraints and weaker government innovation support. The mechanism analysis revealed that the construction of a unified market facilitates the entry of technology enterprises through the effects of talent agglomeration，technology agglomeration，and venture capital agglomeration. Further research uncovered that，in comparison with core cities，the construction of a unified market has a stronger effect on the number and scale of technology enterprises entering peripheral cities，thereby contributing to regional balanced development. The above findings have not only provided a novel perspective for understanding the economic effects of unified national market construction，but also provided insights for the in-depth promotion of unified national market construction and the formulation of policies aimed at regional balanced development.