The Yangtze River Flood Protection Physical Model is built under the financial support of World Bank loan. Based on theoretical analysis and experimental study, a modeling method of flow diversion of the three outlets in Jingjiang Reach under unsteady flow conditions was established for the model. Validation tests under both steady and unsteady flow conditions manifested that with this modeling method, the experimental flow diversion proves to be consistent with that of the prototype and therefore meets the requirements for precision. Being validated, this modeling method has been applied to Yangtze River Flood Protection Physical Model to study the flood routing features in Jingjiang reach.