The classification of waterway grade is a problem that needs to be paid attention to and solved before construction. Conventional projects mainly consider the current situation and trend of water transport development in hinterland，and the classification of conventional projects is determined by superior planning. However，the newly developed canal is usually lacking in planning basis and theoretical analysis. Considering that the canal and natural rivers have obvious different characteristics，we analyze the influence of channel，navigation structure and river-crossing bridges on navigation by guarantee rate method based on the navigable conditions of connecting water system. We accord to the analysis of transportation organization mode and economic variable draft transportation，technical economy，development trend of large-scale ship，transport accessibility，and obtain the classification of canal，which can provide reference for the development of the canal channel project . The results show that the classification of the Pinglu Canal should be I-class and be navigable for 5，000-ton ships.