The invention relates to an assembling structure and method for an integral passenger car safety door. The assembling structure comprises a safety door internal framework and a safety door panel fixed to the safety door internal framework through hinges. An outer retaining strip assembly is arranged on the outer side face of the safety door internal framework. An inner retaining strip assembly is arranged on the inner side face of the safety door internal framework. An outer door panel cover is arranged on the outer side face of the safety door panel. An inner door panel cover is arranged on the inner side face of the safety door panel. The safety door internal framework is provided with waterproof hinge boxes for sealing the hinges in the installation positions of the hinges. According to the technical scheme, through arrangement of the independent safety door internal framework, the related accessories such as the outer retaining strip assembly, the inner retaining strip assembly, the hinges and the safety door panel are assembled to the safety door internal framework firstly so that the integral safety door can be formed, the integral safety door is directly installed on a side wall frame after a whole outer cover is covered, and high-efficiency assembling of the safety door is achieved; and meanwhile, by means of the waterproof hinge boxes, waste of sealing glue is reduced, and the airtightness of the positions of the hinges is improved.