Now the waterway passenger transport of Shenzhen is the national development of the best waterway passenger transport market. With the better understanding of the future of Shenzhen waterway passenger demand trend, we can grasp the development direction of Shenzhen waterway passenger transport more clearly. Based on the gray theory forecasting method, the prediction of the Shenzhen waterway passenger volume is more accurate. It is also proved that the result of prediction in using this model is very credible. The prediction has good feasibility and operability. It will also provide better reference for the development of both waterway passenger transport and other related industries. And then it will provide a scientific basis for Shenzhen waterway passenger to define related development policy.