The invention discloses a technology for producing concrete from wastewater. The technology comprises the following specific steps: (1) collecting wastewater: filtering out gravel in the mud-carried wastewater obtained by cleaning a mixer truck and a mixer through a gravel separator, and feeding the wastewater into a reservoir; (2) detecting concentration: detecting the concentration of solid matters in the wastewater collected in the reservoir in the step (1); if the mass concentration is below 10%, directly applying the wastewater to the step (3); and if the concentration is higher than 10%, diluting the wastewater so that the concentration is below 10%; and (3) applying the wastewater obtained in the step (2) to mixed concrete according to a dosage of 30-70%, wherein the dosage is the percent of the wastewater to the mixing water. According to the technical scheme adopted by the invention, direct economic benefits can be gained, and the problem of water resource shortage can be relieved; and moreover, the environmental pollution caused by wastewater discharge can be reduced so as to realize regeneration and recycling in concrete production and guarantee sustainable development of the construction industry.