Periphytic algae bloom in open channel water delivery system can clog up the sewage barrier, reduce the water delivery capacity, and increase the pressure of clean-up work. At present, most of the research on the response of periphytic algae (PA) to hydrodynamics are carried out in natural rivers and lakes, and studies on the hydrodynamics of PA on the surface of concrete lining are still rare. Due to the significant difference between concrete and sediment substrate, the response characteristics of PA to hydrodynamics in lined open channels and natural water bodies varies. To reveal such different mechanism, the cultivation observation and hydrodynamic erosion experiment of PA in open channel were carried out. By analyzing chlorophyll-a content, community structure, ash-free dry weight and PA cell density, the PA responses to different substrate roughness and different growth stages to different hydrodynamic conditions were investigated. Results showed that there were three distinct stages in the process of colony building, which were lag period, exponential growth period and stable period. With the increase in flow velocity, the PA biomass first increased and then decreased. When the flow velocity was above>0.6 m/s, the PA growth was significantly inhibited. After the erosion velocity increased to 0.8 m/s for 2 days, the PA biomass decreased significantly, and the community diversity decreased. In the retardation period (about 3 weeks in the experiment), the scour and stripping effect of increasing flow velocity on the PA biomass was the most obvious. The smaller the roughness of substrate, the longer the retardation period of PA formation, and the more obvious the effect of PA removal by hydraulic scour. This study explored the PA response rules in open channel under different hydrodynamic conditions, which is helpful to understand the PA community characteristics living in open channel, and can provide an important basis for the hydraulic control of PA living in open channel water delivery system.