Abstract: Abstract: Once the fishway is completed in the traditional style and the flow condition is basically fixed. It will be hard for a variety of fish to go through it at the same time. To solve the problem, in this paper, we developed a Tai Chi fish-way, which can form a rich flow regime and adapt to the migration of many fishes. Based on the ancient Taoist philosophy of “Tai Chi Eight Diagrams”, Tai Chi fishway created a flow changing environment when the eight diagrams rolled, which can offset the general fishway’s shortcoming, “once built, water conditions were basically fixed”. The pool room of the Tai Chi fishway was arc-shaped, which was connected by a reverse arc smoothly. Through the diffusion and aggregation of water, it can help the water flow more smoothly, and reduce the adverse effects of turbulence, vortex and so on. The wall of the pool room was provided with external eight diagrams (groyne type clapboards), which offered resistance to the water flow and helped change its direction when flowing through. The migratory fishes may rest below the external eight diagrams. Tai Chi disk was also set in the pool room and the S shaped channel on the disk had the function of dispersing water flow and dissipating energy. The Tai Chi disk and internal eight diagrams partition can rotate in certain cycles which were combined into different operating conditions at different times to create conditions for the polymorphism of the stream. For Tai Chi fishway had its unique pool room structure, the physical model test alone was difficult to capture the flow structure in detail, and it was time-consuming, too. We used a method combined with the physical model test and numerical simulation to study the flow characteristics of Tai Chi fishway in different conditions. Physical model test was used to study the variation of water level along the course and the basic flow pattern of water flow, and the CFD numerical simulation method was applied to determine the distribution of the surface and internal flow fields which were difficult to be measured by the physical model. Then the water level and flow pattern were compared and verified with each other after being obtained via the two methods. In accordance with the relevant norms of fishway designs and gravity similarity criteria, the fishway physical test models were made. Before the installation of the Tai Chi disc and external and internal eight diagrams, a water test and a measurement of the water depth along the center line were conducted. After the installation of Tai Chi disc, the test was divided into two groups to measure the water depth along the center line. The S shaped channel was approximately parallel and vertical to the flow. In each case, Tai Chi disk placement angle was consistent. The above three situations were simulated by numerical calculation. The results showed that they had a same trend. The maximum error was 13.6%, within the allowable range of 15%. Therefore, the calculation model was reliable and can be used to simulate the complex flow field of the pool room. Therefore, the surface velocity, bottom velocity and critical cross section velocity were further analyzed. The results showed that the Tai Chi fishway had significant energy dissipation reduction effect. The shallowest water depth was about twice of that of the corresponding shallowest water depth without the Taichi disk. Average maximum velocity of cross section decreased by about 50%, the flow presented polymorphism, Tai Chi disk’s different positions also made flow change, which can provide more suitable conditions for migratory fish.