The invention provides a heavy oil hydrogenation demetalization catalyst as well as a preparation method and application of the heavy oil hydrogenation demetalization catalyst. The preparation method comprises the following steps: adding a physical pore-enlarging agent into a metal salt solution containing Mo or W so as to obtain a wet powder pore-enlarging agent; mixing aluminum oxide dry glue powder with the wet powder pore-enlarging agent so as to obtain an aluminum oxide dry glue powder material 1; adding the chemical pore-enlarging agent and a phosphorous compound containing solution to the aluminum oxide dry glue powder so as to obtain an aluminum oxide dry glue powder material 2; mixing the aluminum oxide dry glue powder material 1 with the aluminum oxide dry glue powder material 2 so as to obtain wet materials; drying the wet materials, and roasting so as to obtain an aluminum oxide carrier; and dipping the aluminum oxide carrier into a metal salt solution containing one of Mo and W and/or one of Co and Ni, drying, and roasting, thereby obtaining the heavy oil hydrogenation demetalization catalyst. The invention also provides the heavy oil hydrogenation demetalization catalyst. The catalyst provided by the invention not only has favorable hydrogenation demetalization activity, but also has favorable metal and carbon deposit accommodating performance.