In line with previous studies of the relationship between foreign direct investment (FDI) and global value chains (GVCs), this work uses national panel data of 31 countries along the Belt and Road (B&R countries) from 2010 to 2017 to study the impact of Chinese outside foreign direct investment (OFDI) on the GVC positions of B&R countries and examines the threshold effects of infrastructure level and institutional quality on that impact. The results show that the improvement of B&R countries’ GVC positions is related to Chinese OFDI, and Chinese OFDI has significantly positive dynamic effect on improving the GVC positions of B&R countries. Infrastructure level and institutional quality have double threshold effects upon the effect of Chinese OFDI on improving the GVC positions of B&R countries. When infrastructure level successively exceeds the two thresholds, the effect of Chinese OFDI on improving the GVC positions of B&R countries gradually increases, and when institutional quality successively exceeds the two thresholds, the effect of Chinese OFDI on improving the GVC positions of B&R countries gradually decreases. Our study proposes that under the Belt and Road Initiative, to improve the GVC positions of B&R countries, B&R countries should further strengthen their cooperation with China and continue to attract Chinese OFDI. Moreover, to better play the role of Chinese OFDI in enhancing the GVC positions of B&R countries, China should further strengthen the infrastructure connectivity construction with B&R countries and pay attention to the institutional quality of B&R countries when investing in them.