Under the new development pattern, the “Belt and Road” initiative has become an important driving force to enhance the export competitiveness of China’s manufacturing industry. Therefore, based on the quasi natural experiment of the “Belt and Road” initiative, this study matched multiple databases to collect panel data from 192 countries from 2009 to 2021, and tested the impact of the “Belt and Road” initiative on China’s manufacturing export competitiveness using the multi period double difference model and the intermediary effect model. The results show that: (a) The “Belt and Road” initiative has signifi cantly improved the export competitiveness of China’s manufacturing industry, and this result has passed multiple robustness tests. (b) In terms of impact mechanism, the effect of the “Belt and Road” initiative on improving China’s manufacturing export competitiveness is mainly promoted through policy communication, financial intermediation, facility connectivity and unimpeded trade mechanism, and its contribution rate to the total effect has reached 55.435%, 24.793%, 8.664% and 7.452% respectively. The mechanism of people to people connection has not yet played its due role. (c) The heterogeneity analysis fi nds that, in terms of regions, the promotion effect of the “Belt and Road” initiative on China’s manufacturing export competitiveness is more obvious for countries along the “Belt and Road” and countries with political stability and security; Compared to capital intensive manufacturing products, labor-intensive products have a more signifi cant improvement effect on products.