The present invention provides a preparation method of an antigen composition. The preparation method comprises the following steps: (1) obtaining a tumor antigen protein； (2) making the tumor antigen protein into contact with an immature dendritic cell； (3) inducing the immature dendritic cell in contact with the tumor antigen into a mature dendritic cell； and (4) separating a cell vesicle of the mature dendritic cell. The present invention further provides an antigen composition obtained through the preparation method and the application thereof in preparing a tumor vaccine.
