The invention discloses a recombinant lactic acid bacillus efficiently expressing foot and mouth disease virus antigen genes and a preparation method and application thereof, and belongs to the technical field of biology. The recombinant lactic acid bacillus contains a foot and mouth disease virus VP1 gene sequence, wherein modified lactic acid bacillus signal peptide genes are introduced into the end N of the foot and mouth disease virus VP1 gene sequence, and codon optimization is performed on the foot and mouth disease virus VP1 gene sequence, and the nucleotide sequence is shown in the SEQ ID NO:1. The structure of lactic acid bacillus signal peptide is modified, the modified lactic acid bacillus signal peptide genes are integrated with the foot and mouth disease virus VP1 gene obtained after codon optimization is performed by means of a connection short peptide being GSGGSGG, the integrated gene sequence is inserted into an escherichia coli-lactic acid bacillus shuttle expression vector to construct a recombinant plasmid pSIP/opti-FMDV-A/VP1, and the recombinant plasmid pSIP/opti-FMDV-A/VP1 is converted into lactic acid bacillus. As for a recombinant lactic acid bacillus expression system, the new thought and new method for properly modifying the signal peptide structure to improve the foreign protein secretion efficiency are built, and theoretical basis and technical support are provided for further researching and developing novel mucosal immune vaccines.