On the basis of transcriptome data, the expression of bHLHs of Lepidium apetalum seeds which can tolerate low temperature germination and not between the two groups, were compared, and the family of class bHLH transcription factors in the seeds transcriptome is analyzed in this paper, the laICE1 was one of the bHLH transcription factor gene family members whose relative level of expression in seeds was different between the twogroups significantly. The gene was cloned and its expression was analyzed in response to low temperature stress in L. apetalum seedling. The results showed that: (1) there were 83 family members of bHLH transcription factors in L. apetalum seeds at least. Compared with the low temperature germination stagnation group, there were 17 down regulation, 13 up regulation and 60 bHLH transcription factors with no significant difference in the low temperature germination tolerance group seeds. Among them, the expression of c20009_g1 was down regulated remarkably, and it had an open reading frame composed of 1 503 bp. The sequence was annotated in the GO database with known plant cold related ICE1 genes. C20009_g1 was named laICE1 in this article. (2) Sequence analysis showed that laICE1 encodes a protein consisting of 500 aa with a molecular weight of 54 635.19 kD, a theoretical PI of 5.45, a formula of C₂₃₆₄H₃₇₄₂N₆₈₈O₇₅₈S₂₂, and a conserved domain bHLH. (3) Quantitative analysis by realtime fluorescence showed that the expression of laICE1 was significantly lower in the seeds of the germination tolerance group than that in the seeds of the germination stagnation group. This is consistent with the data of the transcriptome. After low temperature treatment, the expression level of the gene was increased significantly in seedling stage. These results suggest that laICE1 may be related to the ability of the L. apetalum seedlings to tolerate low temperature.