A recombinant yeast strain characterized by overexpression of: (a) a gene encoding a Δ9 desaturase; (b) at least four genes encoding fatty acid elongases; (c) a gene encoding a diglyceride acyltransferase; (d) a gene encoding a fatty acid elongase targeting the endoplasmic reticulum; (e) a gene encoding a diglyceride acyltransferase targeting the endoplasmic reticulum; and (f) a gene encoding a Δ9 desaturase targeting the endoplasmic reticulum, wherein, the gene encoding a Δ9 desaturase is Yarrowia lipolytica SCD, the nucleotide sequence of which is shown in SEQ ID NO: 84; the four genes encoding fatty acid elongases are respectively Mortierella alpina C16/18 elongase gene MaLCE1, the nucleotide sequence of which is shown in SEQ ID NO: 93; Arabidopsis AtFAE1 gene, the nucleotide sequence of which is shown in SEQ ID NO: 94; African mustard BtFAE1 gene, the nucleotide sequence of which is shown in SEQ ID NO: 95; Cardamine mustard CgKCS gene, the nucleotide sequence of which is shown in SEQ ID NO: 96; the gene encoding a diglyceride acyltransferase is Yarrowia lipolytica DGAT1 gene, the nucleotide sequence of which is shown in SEQ ID NO: 83; the gene encoding a fatty acid elongase targeting the endoplasmic reticulum is Cardamine mustard CgKCS ER gene with an encoding sequence for the signal peptide targeting the endoplasmic reticulum, the nucleotide sequence of which is shown in SEQ ID NO: 121; the gene encoding a diglyceride acyltransferase targeting the endoplasmic reticulum is Yarrowia lipolytica DGAT1 ER gene with an encoding sequence for the signal peptide targeting the endoplasmic reticulum, the nucleotide sequence of which is shown in SEQ ID NO: 122; the gene encoding a Δ9 desaturase targeting the endoplasmic reticulum is Yarrowia lipolytica SCD ER gene with an encoding sequence for the signal peptide targeting the endoplasmic reticulum, the nucleotide sequence of which is shown in SEQ ID NO: 123; and the recombinant yeast strain is a recombinant Yarrowia lipolytica strain for producing nervonic acid. (a) a gene encoding a Δ9 desaturase; (b) at least four genes encoding fatty acid elongases; (c) a gene encoding a diglyceride acyltransferase; (d) a gene encoding a fatty acid elongase targeting the endoplasmic reticulum; (e) a gene encoding a diglyceride acyltransferase targeting the endoplasmic reticulum; and (f) a gene encoding a Δ9 desaturase targeting the endoplasmic reticulum, wherein, the gene encoding a Δ9 desaturase is Yarrowia lipolytica SCD, the nucleotide sequence of which is shown in SEQ ID NO: 84; the four genes encoding fatty acid elongases are respectively Mortierella alpina C16/18 elongase gene MaLCE1, the nucleotide sequence of which is shown in SEQ ID NO: 93; Arabidopsis AtFAE1 gene, the nucleotide sequence of which is shown in SEQ ID NO: 94; African mustard BtFAE1 gene, the nucleotide sequence of which is shown in SEQ ID NO: 95; Cardamine mustard CgKCS gene, the nucleotide sequence of which is shown in SEQ ID NO: 96; the gene encoding a diglyceride acyltransferase is Yarrowia lipolytica DGAT1 gene, the nucleotide sequence of which is shown in SEQ ID NO: 83; the gene encoding a fatty acid elongase targeting the endoplasmic reticulum is Cardamine mustard CgKCS ER gene with an encoding sequence for the signal peptide targeting the endoplasmic reticulum, the nucleotide sequence of which is shown in SEQ ID NO: 121; the gene encoding a diglyceride acyltransferase targeting the endoplasmic reticulum is Yarrowia lipolytica DGAT1 ER gene with an encoding sequence for the signal peptide targeting the endoplasmic reticulum, the nucleotide sequence of which is shown in SEQ ID NO: 122; the gene encoding a Δ9 desaturase targeting the endoplasmic reticulum is Yarrowia lipolytica SCD ER gene with an encoding sequence for the signal peptide targeting the endoplasmic reticulum, the nucleotide sequence of which is shown in SEQ ID NO: 123; and the recombinant yeast strain is a recombinant Yarrowia lipolytica strain for producing nervonic acid.