The invention provides antituberculous recombinant bacillus calmette-guerin (BCG delta mazG) with a mazG gene deleted. The mazG gene in a genome of the antituberculous recombinant bacillus calmette-guerin with the mazG gene deleted is replaced with a hygromycin resistant gene. The invention further provides a preparation method of the BCG delta mazG and application thereof in preparing a recombinant vaccine for preventing tuberculosis. After the BCG delta mazG is inoculated subcutaneously into a mouse, a T cell immune response is obviously improved, after the immunized mouse is infected with a mycobacterium tuberculosis standard strain H37Rv, the bacterial load of the infected animal lung and spleen is significantly decreased, the pathological degree is relieved, and after the immunized mouse is infected for five weeks, a T cell secondary immune response is significantly improved. It is found through bacterial in-vivo survival tests that after high-dose intravenous inoculation is conducted, the BCG delta mazG can survive on viscera of the spleen, the lung, the liver and the kidney of the mouse continuously for 20 w or above, and the amount of bacteria of a BCG delta mazG recombinant strain is obviously increased compared with a wild strain. It is proved through experiments that the BCG delta mazG recombinant strain has antituberculous immunogenicity, protective efficacy and in-vivo persistence activity which are significantly improved, and the antituberculous recombinant bacillus calmette-guerin (BCG delta mazG) with the mazG gene deleted is expected to become one of the novel candidate vaccines for preventing tuberculosis infection.