The work aims to deeply understand the mechanical performance of the load-bearing steel structural frame of non-standard packaging box, so as to avoid the failure of packaging box. Here, a non-linear finite element (FE) model of the product-frame interaction was established based on the elastoplastic mechanics by numerical software, and the mechanical performance of the frame under different working environments were studied. In the packaging box, the frame with six lifting points had higher safety, longer fatigue life and less deformation than that with four lifting points. When the product load was close to the designed load of the packaging box, the lifting method with six lifting points was the best choice. The frame failure under lifting or stacking conditions was mainly reflected in strength failure, and the dangerous position was the stress concentration of the butt sharp angle of the section steel, and the load capacity of the frame could be improved by local strengthening at this position. The non-standard packaging box proposed can meet the packaging and transportation requirements of the project, and has obvious economic benefits compared with the conventional packaging and transportation scheme. It is suggested that the lifting acceleration of the research object should be less than 1g.