The invention discloses a space special-shaped arch bridge and a construction method thereof. The space special-shaped arch bridge comprises two supporting structures, a main beam arranged on the twosupporting structures and an arch rib structure arranged on the main beam, the arch rib structure comprises a main arch rib and two auxiliary arch ribs arranged on the two sides of the main arch rib correspondingly, arch feet arranged at the two ends of the auxiliary arch ribs and the main arch ribs are arranged on the upper parts of the middles of the two supporting structures correspondingly, the rise span ratio of the main arch rib is 1 / 5.0-1 / 5.5, and the rise span ratio of the auxiliary arch ribs is 1 / 4.0-1 / 4.5; the main arch rib and the two auxiliary arch ribs are connected through inclined struts correspondingly, and cross struts are arranged on the positions, corresponding to all the inclined struts, between the two auxiliary arch ribs; the main arch rib is connected with the main beam through vertical suspenders, and the two auxiliary arch ribs are connected with the outer sides of the corresponding side of the main beam through inclined suspenders. The space special-shaped arch bridge and the construction method thereof have the characteristics that the structure is light and attractive, the span is large, the bridge is wide, stress is reasonable, and construction is convenient and fast, and the problems that in the existing city view, the bridge pose is single, the cost is high, and construction is difficult are solved.