As the Chinese economy grows rapidly for the past few decades, the traffic congestion problem becomes more and more serious. How to take advantages of the current transportation resources and evaluate their working efficiency is a crucial task facing us, which needs to be solved promptly. This article uses on the grey relational theory to analyze the various factors affecting traffic conditions and to rank these factors by the severity and the order of their impacts, the various input and output factors which have influences on transportation efficiency can be quantified and analyzed, to help us find the best solutions to the traffic congestion issue.