The Arabidopsis peroxisome generate protein mutant pex5 and the wild type was utilized to study the roles of PEX5 in the stress resistance of Arabidopsis roots. The results showed that the root length of pex5 was significantly shorter than that of the wild type in MS medium. At the same time, the height of Arabidopsis pex5 mutant was also lower than that of the wild type, indicating that the deletion of PEX5 affected the root and stem growth of Arabidopsis. When the pex5 was cultured in MS medium with NaCl or mannitol, the inhibition of germination and root elongation was significantly stronger than that of the wild type, and the SOD and POD activity of the mutant seedlings was significantly lower than that of the wild type, which indicated that PEX5 affected the stress resistance of Arabidopsis roots. This study provides an important reference for understanding the regulation mechanism of PEX5 in plant stress resistance.