The invention discloses a method for secretory expression of littin signal peptide-mediated IBV N protein, that is firstly, IBV N gene HBM-N fusing honeybee melittin signal peptide is obtained, then a recombination transfer vector pFast-HBM-N and recombination bacmid rHBM-N are constructed, and finally, the recombination bacmid transfers Sf9 insect cells for secretory expression of IBV N protein. According to the method, the honeybee melittin signal peptide is introduced before IBV N protein, N protein efficient secretory expression is realized, the obtained IBV N protein has excellent biological activity, hydrolysis of endogenous protease to target protein is reduced with the method, purification is facilitated, the foundation is laid for further study of N protein biological functions, development of novel diagnostic antigen, development of novel vaccine and the like, and at the same time, a new thought is provided for expression of other structural protein of the IBV.