Concerning the problem that the manual design of airport arrival procedures is time consuming and it is difficult to optimize the path length quantitatively， a three-dimensional automatic optimization design method of multiple arrival procedures was proposed. Firstly， based on the specifications of RNAV （Rules for implementation of area NAVigation）， the geometric configuration and the merging structure of the arrival procedures were modeled. Then， considering airport layout and aircraft operation constraints such as obstacle avoidance and route separation， with the goal of minimizing the total length of arrival procedures， a complete mathematical model was established. Finally， a hybrid algorithm based on simulated annealing algorithm and improved A^* algorithm was developed to automatically optimize the merging structure of arrival procedures. Simulation results show that， in the experiment based on Sweden Arlanda Airport， compared with the existing related integer programming method， the hybrid simulated annealing algorithm can shorten the total path length by 3% and reduce the computing time by 87%. In the experiment based on Shanghai Pudong Airport， compared with the actual arrival procedures， the length of the routes designed by the proposed algorithm is reduced by 6.6%. These results indicate that the proposed algorithm can effectively design multiple three-dimensional arrival procedures， and can provide preliminary decision support for the procedure designers.