The Trihelix family is a specific family of transcription factors in plants, and plays an important regulatory role in plant growth, development, and stress resistance. Based on the genome database of birch, this study analyzed the expression characteristics and disease resistance function of birch Trihelix family genes, which laid the foundation for the research on the function of Trihelix family members in the disease resistance process of birch. The results showed that: (1) a total of 8 Trihelix family members (BpTrihelix1-BpTrihelix8) were distributed on 6 chromosomes; the molecular weight of amino acids is between 35 633.96-81 871.27 Da, and the isoelectric point is 5.32-8.67, all of which are hydrophobic amino acids. (2) Tissuespecific expression analysis showed that eight family members are expressed in different degrees in the roots, stems, and leaves of birch, and BpTrihelix3 have the highest expression level in roots, stems, and leaves. (3) The results of the pathogen infection test showed that BpTrihelix3, BpTrihelix4 and BpTrihelix7 were significantly upregulated when Alternaria alternata infected the leaves of birch for 48 h and Rhizoctonia solani infected roots of birch seedlings for 24 h, and the expression level of the rest of the family genes did not change significantly, indicating that among the gene members of this family, BpTrihelix3, BpTrihelix4 and BpTrihelix7 responded to the infection of pathogenic bacteria, so we speculated that they might play an important role in the disease resistance procress of birch.