The invention discloses a wastewater treatment device for building construction, which comprises a silt treatment mechanism, a water flow channel, a water pump, a flocculation stirring mechanism, a pollution discharge purification mechanism, a communication pipeline and a valve II, and is characterized in that the water flow channel is arranged on one side of the silt treatment mechanism; the water pump is arranged on one side of the water flow channel, the flocculation stirring mechanism is arranged on the other side of the water flow channel, the pollution discharge purification mechanism is arranged on one side of the flocculation stirring mechanism, the communicating pipeline is arranged between the flocculation stirring mechanism and the pollution discharge purification mechanism, and the valve II is arranged on one side of the communicating pipeline; according to the invention, gravel is fully blocked and filtered, blockage in the filtering process is prevented, insufficient stirring caused by vortex is prevented in the stirring process, and the stability and safety of equipment can be ensured.