Abstract: The high-performance turf-reinforced mat (HPTRM) is a new type of strengthening material which has been widely used in recent years to protect the vegetation linings and enhance their anti-erosion ability. The existing studies on the erosion resistance of the vegetated HPTRM systems are mainly based on the large-scale tests and focus on the permissible flow velocity and shear stress. In order to study the erosion process of the vegetated HPTRM system under the high-speed open channel flow conditions, a total of 48 specimens of natural vegetation and three types of vegetated HPTRM systems are cultivated. In a special flume designed to generate the high-speed open-channel flow, continuous and discontinuous flushing tests are carried out under different slopes and discharges. During the testing, the erosion depths of specimens, the flow discharges and flow surface velocities are recorded. The differences in erosion rates between the continuous and discontinuous tests indicate that the first flushing of the flow, which means the process of no flow to flow, induces most of the erosion of the vegetated HPTRM systems. The erosion processes of the specimens show a decrease of the erosion rate with the increase in the erosion depth, which proves the existence of the "upper limit" of erosion, which can be explained by the exposure of HPTRM and consequent increase of the anti-erosion ability. We have also discussed the influences of the flow discharges and HPTRM structures on the erosion processes, and try to fit the relationships between the average erosion rate and the flow surface velocity with the linear relationships.