The work aims to obtain W-type and C-type multi-cell thin-walled square tubes with different configurations through the introduction of side coefficient γ to improve the energy absorption efficiency of multi-cell thin-walled square tubes. Experimental and numerical methods were adopted to study two types of square tubes made of 6060T4 aluminum alloy. The effects of side coefficient γ and wall thickness t on the mechanical performance, energy absorption and deformation mode of the structure were analyzed in depth. Then, the Non-dominated Sorting Genetic Algorithm (NSGA-Ⅱ) was used to analyze the thin-walled square tubes. Multi-objective optimization was carried out for the peak load (Pc) and specific energy absorption (Sa). The load curves obtained by numerical simulation were consistent with the experimental results. There were 7 folded waves. The side coefficient γ had a significant influence on the load and deformation of class 2 structures. The results obtained in this work provide data support for improving the buffering energy absorption and impact protection of thin-walled square tube structures.