The invention relates to a composite mineral admixture based on gneiss powder, and belongs to the technical field of building materials. The composite mineral admixture is prepared from the following raw materials in percentage by weight: 60 to 80 percent of gneiss powder, 10 to 20 percent of pulverized fuel ash, 10 to 20 percent of ground slag powder, 5 to 10 percent of limestone flour, 0 to 5 percent of functional superfine powder and 0 to 5 percent of silica fume. The fineness, activity index and mobility ratio of the composite mineral admixture meet the current standard requirements of the composite mineral admixture, waste gneiss powder produced in the production process of machine-made sand can be utilized reasonably and effectively, and meanwhile the performance of concrete can be improved at a certain degree.