The three Gorges Reservoir runs at the water level of 145-175 m all year round，and the bank slopes in the reservoir area are periodically submerged and exposed. The fall of the water level in reservoir causes the seepage of the soil bank slope，and the sediment is easier to start and aggravate the erosion of the reservoir bank. The bank slope is unstable in serious places. Taking the soil bank slope in the Three Gorges Reservoir area as the research object，aiming at the characteristics of the new ecological slope protection structure—terra block mat slope protection，the indoor generalized model test is used to study the protective performance of the terra block mat under the action of seepage. The soil—retaining and anti-scour performance of terra block mat is analysed through water scouring test under seepage action. The test results show that the terra block mat has good soil retention and anti-erosion performance；water flow erosion intensity is reduced by an average of 83.15% under the condition of no seepage，and is reduced by an average of 88.15% under the action of seepage.