The invention discloses an unpowered vacuum-energy flying saucer type spacecraft. The unpowered vacuum-energy flying saucer type spacecraft comprises a flying saucer type body, a central control room and a rotating device, wherein flying saucer type body comprises an inner layer and an outer layer, and an interlayer is formed between the inner layer and the outer layer; the flying saucer type body, the central control room and the rotating device form a flying saucer shape in an enclosed manner; the flying saucer type body is of a miniature flying saucer shape when the interlayer is not filled with gas, the flying saucer type body is of a large flying saucer shape when the interlayer is filled with gas, and an energy accumulation system is arranged in the central control room. The unpowered vacuum-energy flying saucer type spacecraft has the advantages that the spacecraft can fly by using the interchanging of vacuum energy and gravity energy under an unpowered condition, wave type or spiral type flying is achieved through energy accumulation and conversion, flying directions are controlled through the energy accumulation and conversion, and a UFO flying effect is achieved.