The invention relates to a combined composite brake disc, a preparation method and application, and belongs to the technical field of development of special brake discs. The combined composite brake disc comprises a friction disc body (1) and a connecting and supporting disc body (2). The friction disc body (1) is of a carbon-ceramic composite, and the connecting and supporting disc body (2) is of a gradient aluminum matrix composite compounded in a hot-pressing mode. The combined composite brake disc comprises the friction disc body (1) of the carbon-ceramic composite and the connecting and supporting disc body (2) of the gradient aluminum matrix composite. The friction disc body (1) of the carbon-ceramic composite and the connecting and supporting disc body (2) of the gradient aluminum matrix composite are connected into a whole through riveting. The brake disc designed in the invention is obviously longer than existing products in service life when being applied to high-speed trains.