The calculated result of flood routing based on mathematical model is usually expressed in numerical values which indicate water level and flow velocity field. In order to discover the regularity of flood progression, visualization tools are used to make values be expressed impressively by graphics. In this paper, the dynamic visualization of flood is based on Vega Prime software which is a virtual reality platform. Technical framework and realization of methods about dynamic visualization are researched and tested by an illustration. The results show that this method can achieve a better visual expression of the flow field.