In order to further improve the aerodynamic efficiency of cycloidal rotor, its design parameters are optimized. Firstly, the basic principles of tube model for the cycloidal rotor are analyzed. Based on the theory of thin-aerofoil oscillation, an unsteadily aerodynamic dual disk multi-flow tube model for the cycloidal rotor is established by combining the momentum with the blade element theory. Then, the model applicability is verified with relevant examples. The results show that the accuracy is relatively high when the solidity is relatively low, and error value is increased as the interference among the blades is strengthened because of the increasing solidity and rotation speed. The thrust correction factor of the multitube model at different solidity is summarized via the comparison between a large number of experimental and computational data. Finally, based on the dual disk multi-flow tube aerodynamic model, the genetic algorithm is used to carry out the optimization design for the relevant design parameters of cycloidal rotor. The power load after optimization is increased by 7.9%. Meanwhile, it is found that the optimized cycloidal rotor has the higher aerodynamic efficiency than the rotor.