The invention belongs to the field of pile cutting technologies for shields, and particularly relates to a tool configuration method for soft-soil stratum shields for directly cutting large-diameter pile foundations. The tool configuration method includes steps of selecting seashell advancing tools to be used as pile cutting tools, and determining the sizes of the tools; configuring front pile cutting tools in a concentric circle equidistant manner; configuring main leading pile cutting tools with the preferable leading quantities of 3d approximately; configuring auxiliary leading pile cutting tools on two edges of a temporary side of each main leading pile cutting tool. The tool configuration method has the advantages that the shields can feasibly directly cut the large-diameter pile foundations, concrete foundation bodies can be cut in a full coverage manner, reinforcing steel bars can be cut according to designed lengths, and the tool configuration method is efficient, simple and economical.