Ocean shipping plays a dominant role on Taiwan international cargo transportation that is essential to the economy growth of the island. Statistics show that more than 99% of import and export freight is shipped through ocean transportation. Lots of efforts have been made on the analysis of import and export cargo volumes based on an island-wide scope or by harbors. This research takes a step further by investigating specific lines. The analysis focuses on the three most import lines: Taiwan-U.S.A., Taiwan-Japan and Taiwan-Hong Kong. Time-series data from the three lines are used to examine the trend during the past decade, and econometric models are employed to determine factors that have a bearing on containerized cargo volumes. Results indicate that while total volume witnesses a continuous increase in the past, variations among different lines exist. Additionally, volumes in different lines are not influenced by the same factors. The research results reveal the necessity of investigation by lines, and provide useful information for future research on cargo volume forecasting.