The invention discloses a space truss multi-barrel base of an offshore wind power unit, which mainly comprises a connecting cylinder, three suction barrels arranged in a triangle shape or four suction barrels arranged in a quadrangle shape, and support pillars the number of which is the same as that of the suction barrels, wherein each suction barrel is fixedly connected with the connecting cylinder through the corresponding support pillar; and a support member with a truss structure is connected between every two support pillars. The invention is of an integrated structure which consists of a space truss system and a multi-suction-barrel base, transfers the overturning load suffered by the whole base into vertical underdraught and up-pull load on single-barrel base, fully utilizes the superiority of multi-barrel base for bearing vertical load, has the advantages that the bearing load of the structure is reasonable, and solves the difficulties that the construction cost of the offshore wind power unit is high and the construction is complicated.