An adjustable rotation base includes a base housing and a transportation arrangement. The base housing has a bottom side, an upper side for coupling with the supporting post to support the outer umbrella in an upright manner, and a receiving cavity indently formed on the bottom side of the base housing, wherein the base housing includes a stationary unit provided at the bottom side for sitting on the ground surface in a stationary manner, and a plurality of transferring wheels rotatably supported at the bottom side of the base housing. The transportation arrangement is provided at the base housing to operate the base housing between an idle mode and a transportation mode in which the stationary unit is upwardly lifted to allow the transferring wheels being sitting on the ground surface, such that the base housing is adapted to be transported on the ground surface via the transferring wheels.