Abstract:"Soft connectivity" through standards is an important support for promoting the high-quality development of the "the Belt and Road" connectivity. Based on the perspective of differences in standard technical attributes, this paper uses the panel data of 45 countries along the "Belt and Road" from 2006 to 2019 to analyze the mechanism of standard output on the total factor productivity of countries along the "Belt and Road". The main conclusions are as follows: (1) China's standard output has a long-term promoting effect on the total factor productivity of countries along the "Belt and Road", mainly through enhancing technical efficiency and scale efficiency. (2) Consistent standards and unique standards have a pulling effect on the productivity improvement of countries along the "Belt and Road", and the pulling effect of consistent standards is stronger than that of unique standards. Consistent standards mainly promote technical efficiency and scale efficiency, while unique standards mainly promote technological progress. (3) Standard output has a strong pulling effect on low technology, low standards and non-EU countries. The pull effect of unique standards on high-tech and high-standard countries is better than that of consistent standards, while the pull effect of consistent standards on low-tech, low-standard and non-EU countries is better than that of unique standards. This paper not only reveals the mechanism of standard output improving the total factor productivity of countries along the "Belt and Road", but also provides theoretical support for how to optimize standard output and promote high-quality interconnection.