To address the low efficiency of fish passage caused by poor flow conditions,this study proposes a new kind of fishway design,named as the L-shaped baffle fishway.The water flow conditions inside the fishway are investigated by numerical simulation.The results show that the flow is stable and maintained in the center of L-shaped baffle fishway.There are similar and stable recirculation zones on both sides of the main stream,with the lowest velocity occurring in the center of recirculation zone.The main flow width of 0.45 m,which is comparable to the vertical slots of the L-shaped baffle fishway,and the hydraulic properties of the individual water layers are essentially the same.The maximum mean flow velocity of the fishway decreases with the decrease of bottom slope.When the bottom slope decreases from 1/70 to 1/90,the maximum flow velocity of the fishway decreases from 1.06 m/s to 0.91 m/s,which is a decrease of 16.5%.When the bottom slope is lower than 1/80,the turbulent kinetic energy in the main flow region keeps at 0.05 m2/s2，the turbulent kinetic energy in the pool is less than 0.05 m2/s2，and the low turbulent kinetic energy area is more than 70%.This study can provide quantifiable design parameters for the fishway project.In combination with the requirements of design specifications,when the bottom slope of the fishway is 1/80 or less,it can meet the upstream requirements of fish.