The complete interchangeability of civil aircraft cabin doors can effectively reduce production and operational costs, advanced foreign aircraft have been able to achieve complete interchangeability of large cabin doors, the manufacturing of cabin doors in China still generally adopts the method of trimming the skin, and complete interchangeability has not yet been achieved. In order to improve the competitiveness of aviation products，it is imperative to realize the complete interchangeability of cabin doors.The technical difficulties in the design of completely interchangeable doors were analyzed，a solution of completely interchangeable doors were given, including an implementation process flow chart and decomposition description. The key technologies of completely interchangeable door were described in detail, such as door installation and adjustment technology mainly based on six degree of freedom attitude adjustment, tolerance management technology based on cumulative tolerance calculation, key part design compensation technology based on door installation adjustment results，tolerance management results and stiffness matching results of cabin doors. These technologies provide references for the design of civil aircraft completely interchangeable door. It can be promoted and applied to the design of semi plug and other forms of cabin doors in civil aircraft.