Door stops are important structure parts in civil aircraft, which transfer the pressurized load from door to frame through face-to-face contact. The reliability of door stops is quite crucial for flight safety. For the face-to-face contact problem, contact clearance affects the load distribution, meanwhile the life is very sensitive to the load variation. The influence of clearance to the load and fatigue life of door stop is lacking in previous studies. In this paper, the door stop of some aircraft was studied. The detailed finite element model was established, in which the linear gap and the superelement method were introduced; the mathematical approach describing the clearance randomness was proposed, and the Monte Carlo simulation was carried out to analyze the influence to the stop load; the fatigue life varying with clearance was computed using DFR method, the design approach of allowable clearance under target life was proposed. The work of this paper can provide a reference for the clearance design of door stop.