The invention relates to universal influenza vaccine and a preparation method thereof. After an influenza virus HA is subjected to gene transfection to eukaryocyte, influenza haemagglutinin (HA) protein subjected to eukaryotic expression modification is inserted into a host plasma membrane, then vesicles largely displaying influenza virus envelope glycoprotein is produced with a method that a surface active agent induces a cell to bud, and the vesicles are changed into controllable and nanometer mimicry virus vesicles with uniform dimensions after purification and re-adding of the surface active agent for treatment. At the same time, by the aid of establishment of stably expressing an HA cell strain and usage of a bioreactor, the method is also applicable to large scale influenza vaccine production. The method is simple and feasible, hemagglutinin of most influenza virus (including avian influenza and swine influenza) can be displayed, and the method has excellent universality, has a great potential and can be used for designing emerging highly lethal influenza virus vaccines.