The invention discloses an ultra-span greenhouse and relates to a greenhouse for planting. The greenhouse comprises main support columns, outer struts, a middle beam, greenhouse main frames, an oblique bracing wire, a bow-shaped beam, a lower tension chord, a support rod and a plastic film, wherein the main support columns are ranged in a line; the outer struts are arranged at both sides of the main support columns; the middle beam is installed between the main support columns; one ends of the greenhouse main frames are installed on the outer struts, and the other ends are installed on the main support columns and the middle beam; the bow-shaped beam is installed between the adjacent greenhouse main frames; the main support columns are connected with the adjacent greenhouse main frames bythe oblique bracing wire; both ends of each greenhouse main frame are connected with the lower tension chord, the lower tension chord is transversely drawn at the lower part, and the support rod is installed between the bow-shaped beam and the lower tension chord; and the plastic film is installed outside the frame to form the greenhouse. The green house can effectively increase the span of the greenhouse beam by adopting a frame type structure and an oblique bracing wire structure.