The invention discloses a method for constructing an independent pile tower crane foundation supported on an excavation slope. The steps are as follows: geologic drilling analysis is carried out on the excavation slope to draw up a construction scheme; according to the scheme, holes are dug on the excavation slope, water is pumped during the operation of digging the holes, retaining wall moulding boards are supported, and concrete retaining walls are cast. The diameter of each hole bottom is enlarged, and backing concrete is cast to form an expansion head. Independent supporting piles and the tower crane bearing foundation are cast by the concrete, the diameter of the independent supporting pile is equal to or larger than 1.42 times of the side length of each standard knot of a tower body, the depth of the independent supporting pile is equal to or larger than 1.5 times of the height of a pile foundation suspension arm, and the top face of the tower crane bearing foundation is lower than a natural terrace. The construction method has the advantages of low production cost, reliable quality, simple machines and equipment, convenient construction and operation and higher single-pile bearing force, thereby meeting the requirement of casting the tower crane bearing platform foundation; and the construction method has no noise during construction, no discharge of mud solution, little effect on ambient environment and buildings and small space occupation.