There are different requirements for normal opening handle force and unsafe pressure opening handle force of civil aircraft pressurized cabin door, it is difficult to meet the requirements of normal opening and unsafe pressure opening handle force by relying on the door opening mechanism design. In order to meet the requirements of airworthiness regulations and improve the maneuverability of the cabin door, it is necessary to design pressure lock mechanism which can lock the fully closed position of the cabin door in the pressurized state.The design requirements of the pressure lock mechanism were given, and the mechanism characteristics of two different types of pressurized cabin door were analyzed respectively. Based on the mechanism characteristics, the design ideas of two different types of pressure locking mechanisms were given. On this basis, two different forms of pressure locking mechanisms “integrated in the pressurized pre defense door” and “locking handle” were provided. The mechanism form and the composition of mechanism were introduced, and the movement principle and working process of the pressure lock mechanism were analyzed.The mechanisms can meet the design requirements, which provides a reference for the design of door pressure lock mechanism and it has practical value.