The invention provides a building method for a radial type foundation structure of a tall building. The building method sequentially comprises the following steps that S1, a plurality of continuous walls are built underground, wherein the continuous walls extend in the up-down direction and are connected in an intersected manner at the same intersecting point; and S2, a cover plate is built on the upper end faces of the continuous wall. In the step S1, after the continuous walls are built, the following step is included, the following step is that S14, a grade beam is built between two adjacent continuous walls, the intersecting point of the multiple continuous walls is located at the middle portions of the continuous walls, and the center point of the cover plate corresponds to the intersecting point in position. The building method for the radial type foundation structure of the tall building is simple in operation and convenient to implement; and meanwhile, the multiple continuous walls are connected in the intersected manner at the same intersecting point, namely the multiple continuous walls are connected in the intersected manner in a radial type, so that the radial type foundation structure of the tall building has the high connection strength, the high supporting strength and the high whole stability.