Abstract: The present disclosure relates to use of a multigene stacking method in synthesis of nervonic acid in Brassica napus. The present disclosure provides a multigene co-expression plant vector, including an initial backbone of pBWA(V)BII and multiple exogenous gene expression cassettes. The present disclosure further provides two plant vectors applicable to genetic transformation, including a three-gene co-expression plant vector and a five-gene co-expression plant vector. In the present disclosure, after the three-gene co-expression plant vector and the five-gene co-expression plant vector are separately transferred into the Brassica napus, the nervonic acid (NA) with a high content is synthesized in the Brassica napus through multigene co-expression. An NA ratio can be significantly increased combined with a higher seed oil content and a greater field seed yield. The plant vector realizes efficient synthesis of NA in oil crops, obtains NA-rich seed oil, and increases an added value of edible oil.