The study is based on the transcriptome data of Saussurea involucrata, using Premier 5.0 designing a pair of specific primers SiICE2Up and SiICE2Down, Using S. involucrata cDNA as a template and the open reading frame (ORF) of the S. involucrata SiICE2 gene was cloned and analyzed with bioinformatics. Plant expression vector pCAMBIA230035SSiICE2Nos was constructed and then introduced into tomato (Lycopersicon esculentum) by using Agrobacteriummediated transformation. Identification of transgenic plants by PCR and RTPCR. The relative expression level of SiICE2 gene in transgenic tomato lines was analyzed by qRTPCR. The cold resistance analysis was performed after the transgenic and wildtype tomatoes were treated at 0 ℃. The results show: (1) cloning of the S. involucrata SiICE2 gene and the opening reading frame (OFR) of the SiICE2 gene is 462 bp which encoded a deduced protein including 153 acids residues. Phylogenetic analysis revealed that the SiICE2 gene is closely related to Cynara scolymus L. (2) Plant expression vector pCAMBIA230035SSiICE2Nos was constructed and then introduced into tomato by using Agrobacteriummediated transformation. There are 9 strains of tomato plants of transgenic SiICE2 gene detected by PCR. (3) Membrane physiological index showed that the relative electrical conductivity and MDA content of the transgenic tomato were significantly lower than that of the wild type with the increase of the low temperature treatment time. The relative conductivity ratio of the transgenic tomato was 31.7% lower and the malondialdehyde content was 4.2 μmol/g lower than that of wild type at the treatment time of 24 hours. (4) Antioxidant enzyme activity assay showed that the POD, CAT and SOD activities of the transgenic tomato plants continuously increasing with the increase of the low temperature treatment time. The activities of transgenic POD, CAT and SOD were significantly higher than those of the wild type at each treatment time, and the wild type showed a trend of gradually increasing and then decreasing. The study found that the S. involucrata SiICE2 gene can significantly enhance the cold resistance of noncold domesticated tomatoes.