The invention discloses a fully-automatic assembling and abutting-joint method based on an air flotation technology and aims at solving the problems that the assembling efficiency is low, the flexible degree is relatively low, the assembling quality is limited by an assembling technology of a worker, an assembling process seriously depends on the engineering experience of operating staff and heavy mechanical equipment, a six-degree-of-freedom abutting-joint and assembling regulating mechanism depends on relatively high machining capability, the cost is high and the working difficulty is high because of manual abutting-joint and assembling adopted in the prior art. The method is realized according to the following steps: clamping cabin sections; acquiring stress states of the cabin sections; calculating the deviation of position postures of the cabin sections; judging a deflection angle around the Y direction, a deflection angle around the Z direction, a deflection angle around the X direction and a position deviation around the Z-axis direction and the Y-axis direction between an active cabin section and a passive cabin section; acquiring position postures of the active cabin section and the passive cabin section; calculating the deviation of the position postures of the active cabin section and the passive cabin section and the advancing step length of the active cabin section to complete abutting-joint. The fully-automatic assembling and abutting-joint method based on the air flotation technology is used in the field of flexible assembly.