The invention relates to a well drilling wastewater flocculation precipitation treatment device. The device comprises a flocculation reaction tank, a flocculation settling basin and an intermediate tank, the flocculation reaction tank is provided with a stirring device, the flocculation settling basin and the intermediate tank are arranged on a well site, the flocculation reaction tank is provided with a water feeding port, a chemical feed port and a water discharge port, the water feeding port, the chemical feed port and the water discharge port are communicated to the outside, a communication valve is arranged between the flocculation settling basin and the intermediate tank, a first water pump is disposed between the flocculation settling basin and the flocculation reaction tank, the flocculation settling basin is communicated with a water inlet end of the first water pump, a water outlet end of the first water pump is communicated with the flocculation reaction tank, the flocculation reaction tank is communicated with the flocculation settling basin and the intermediate tank which are arranged on the well site to form a water circulation to collaboratively store water bodies, defects that the transportation is difficult, and uniform stirring is hardly achieved when the flocculation reaction tank is oversize are overcome, the required volume of the flocculation settling basin is reduced, besides, the water bodies formed by well drilling wastewater and flocculating agents are maintained in a flow state all the time, and the dissolving efficiency of the flocculating agents is improved.