The invention discloses a three-dimensional quantum cellular automata adder, which comprises seven quantum cellular automata connecting lines, a two-dimensional majority logic gate, a two-layer three-dimensional majority logic gate, a three-layer three--dimensional majority logic gate, a first three-dimensional phase inverter, a second three-dimensional phase inverter, a third three-dimensional phase inverter, a fourth three-dimensional phase inverter, a first two-dimensional phase inverter and a second two-dimensional phase inverter. Compared with a traditional two-dimensional quantum cellular automata adder, the three-dimensional quantum cellular automata adder provides an extra one-dimensional computation space, so that fewer cells are required, and meanwhile, the space and the power consumption of a circuit are drastically reduced. The three-dimensional quantum cellular automata adder is a novel quantum cellular automata adder which has the advantages of being low in three-dimensional power consumption and small in area.