The present invention discloses a foundation treatment method for exactly regulating foundation settlement, and a construction device, and belongs to the technical field of civil engineering. According to the method, the number of squeezing expanding apparatuses and the amount of diameter expansion are determined according to settlement prediction of the foundation to be eliminated; with gradual expansions of the squeezing and expanding apparatuses in the soil according to the specified rates, horizontal loads are applied on the surrounding soil, such that the soil is forced to be subjected to drainage consolidation, the porosity is reduced until the pore reduction meet the design target value so as to realize a purpose of exact regulation of the foundation settlement. The construction device is the squeezing and expanding apparatus. The squeezing and expanding apparatus comprises at least an II type squeezing and expanding apparatus unit, which can form an oblique extension type diameter-variable pile pore after expanding. According to the present invention, with diameter-variable squeezing and expanding, according to the preset target, the pores in the foundation are exactly andquantitatively eliminated so as to achieve the purpose of exact regulation of the foundation settlement prediction; for the road widening project, the settlement difference between the old road foundation and the new road foundation can be exactly controlled; the construction device is convenient, the construction method is simple and the cost is low.