COSCO and China Shipping Container Lines (CSCL) merged and reorganized as COSCO Shipping Lines in 2016. Through using a complex network methodology, we analyze the spatial patterns of their shipping networks before and after the merger. We evaluate the integration effects based on two main dimensions: network and hub economies. While complementarities are found between COSCO and CSCL networks before the merger, COSCO Shipping Lines increased the total number of service nodes and shipping routes significantly. The merger also had the effect of strengthening the hub capacity of 7 of the top 15 hub ports in the main markets covered by the new company. Results underline that this strategy of overseas pivotal ports promoted the development of hub economy and regional market expansion.