The invention discloses a double waverider splicing air suction type hypersonic aircraft forebody and a design method thereof. The double waverider splicing air suction type hypersonic aircraft forebody comprises a left waverider, a right waverider, a splicing surface and an upper wall surface, wherein the left waverider and the right waverider are symmetrically arranged at preset intervals; the splicing surface is formed between the lower front edge lines of the left waverider and the right waverider; the splicing surface is used for seaming the gap between the lower front edge lines of the left waverider and the right waverider and serves as a lifting surface of the forebody to provide addition lifting force; the upper wall surface is formed between the front edge line of the splicing surface and the upper front edge lines of the left waverider and the right waverider; and the upper wall surface is used for seaming the gap between the upper front edge lines of the left waverider and the right waverider. The double waverider structure is formed, and the splicing surface and the upper wall surface for reasonably seaming the gap between the lower front edge lines of the left waverider and the right waverider and capable of improving the pneumatic/volume comprehensive performance of the aircraft are formed between the double waveriders, so that utilization of abdominal space of the aircraft can be improved well.