Over 80% of global trade is carried by sea, and 70% of global seaborne trade by value is realized by liner shipping. The global liner shipping network (GLSN) is essential to facilitating international trade. To explore the transportation mechanism of the GLSN, we study a structure termed “two-hop biconnected component”(TBCC) which is a type of highly robust and efficient connected local structure. We find that TBCC is a salient structural property of the GLSN and is strongly associated with international trade statuses. Ports that appear more frequently in TBCCs tend to gain higher container throughputs in reality and play more important roles in maintaining the overall network robustness. Furthermore, we find that countries belonging to the same TBCCs tend to have closer trading relationships and form meaningful multilateral trade clusters in the future. The discovery of TBCC can help better understand international trade statuses and enable better design of robust and efficient liner shipping service routes.