In the first time passing through of the Great Canyon in the world and the investigating on its whole course by chinese scientists, some important results were obtained. Four great groups of waterfalls were discovered. The historical records of the Great Canyon were reviewed. Three basic characteristics of the newly discovered four groups of waterfalls were gencralized. The analysis on the cause of the formation of the Great Canyon indicates that they have different river bed geomorphology caused by the selection and creation of great waterpower act and they are one of the marvellous natural phenomena in the world.