Dewatering well construction method, dewatering well and dewatering well system

The invention provides a precipitation well construction method, a precipitation well and a precipitation well system. The method comprises the steps that drilling and punching of a first preset hole diameter are carried out at a preset position, and a drilled hole is obtained; when the depth of the drill hole reaches the position of the top plate of the aquifer, clear water is added into the drill hole for slurry making, and first slurry is formed in the current drill hole so as to support the hole wall of the current drill hole; when the depth of the drilled hole reaches the preset depth, the current drilled hole is expanded, a formed hole is obtained, the expanded hole depth is the preset well depth, the preset well depth is larger than 100 m, the expanded hole diameter is the second preset hole diameter, and the second preset hole diameter is larger than the first preset hole diameter; and a sand setting pipe and a water filtering pipe are installed in the formed hole, the outer wall of the water filterin