以低毒性、低成本尿素部分替代三聚氰胺合成了改进型ＳＭ系混凝土减水剂，研究了其合成工艺及参数，及该减水剂对混凝土相关性能的影响．结果表明，该减水剂具有显著减水作用，减水率高达３５．７％，原料成本降低２２％，且具有低毒的优点，显示出明显的工业化前景 An improved SM-series concrete water reducer was synthesized by partially replacing melamine with low toxicity and low-cost urea. Its synthesis process and parameters were studied, and the influence of the water reducer on the properties of the concrete was also studied. The results show that the water reducer has a significant water reducing effect, the water reduction rate is as high as 35.7%, the raw material cost is reduced by 22%, and it has the advantages of low toxicity and shows a clear industrialization prospect.