Abstract: As there are many indicators with very high correlation to evaluate urban transport sustainable development level, which make the indicators system's dimensionality reduction possible.By using Principal Component Analysis, this paper classifies 23 evaluation indicators of Chengdu urban transport into 3 principal components with a meaningful explanation.Then the principal component score curve is used to compare traffic sustainable development of Chengdu in different periods and the volatilities which affect Chengdu' s traffic sustainable development are obtained.The method mentioned in this article can objectively evaluate sustainable development for urban traffic without fuzzy analysis.