The horizontal axis tidal turbine is a typical apparatus to capture the energy in the ocean, but most traditional design methods of a turbine blade have led to the inefficiency of turbines. Therefore, to improve turbine efficiency, a design methodology of a horizontal axis tidal turbine blade based on bionics research is presented in this work. First, the point cloud of fin samples was scanned and processed. The three-dimensional digital models of pectoral and causal fins were extracted by reverse engineering software. Then, the bionic airfoil blade model was obtained through parameter optimization and coordinate transformation and a shark fin airfoil blade based on the bionic principle was designed, which provided a new method for the turbine blade design. Finally, the hydrodynamic performance of the bionic airfoil turbines at different pitch angles was studied through numerical simulations and underwater experiments, and the results showed that the performance of bionic airfoil turbines designed in this paper was better than that of the traditional blade turbines.