The invention discloses a method of additively manufacturing metal composite board with a built-in circuit and belongs to the field of additively manufacturing. A technical problem is solved by providing such method, by which a circuit is directly wrote to the metal composite board, so that the circuit and the metal composite board are manufactured at the same time to form the integrated metal composite board with the built-in circuit via the additively manufacturing. In one technical scheme for solving the problem, the method includes the steps of: pre-cutting preset circuit paths in a metalfoil material; performing ultrasonic consolidation shaping to the metal foil material; and successively filling the circuit paths with an insulation material, a conductive material and an insulation material, and integrating the circuit with the metal composite board. The method can be widely applied to the field of additively manufacturing.