The current Conventional Step-down procedure has been unable to meet the requirements of safety, economy, environmental protection and comfort with the rapidly development of the global civil aviation industry. It is concluded that the Continuous Descent Operation (CDO) procedure is better than the Conventional Step-down procedure in comparison with the Conventional Step-down procedure. The feasibility has been proved by the theory analysis and the relevant flight test experiments. Finally, it is concluded that the Continuous Descent Operation is feasible and will become the development trend of civil aviation in the future.