Taking representative domestic slag powder (SP) as the object, properties such as heavy metal risk, volcanic ash activity, and dry shrinkage model construction were studied. The SP samples are mainly composed of three chemical components: silicon dioxide, aluminum oxide, and calcium oxide. Collectively, these three oxides constitute 85 % of the total chemical composition of the samples. Heavy metal risk assessment show that SP poses no direct risk to the external environment. However, considering that the measured values of Cr, Ni, and Pb are the highest and there is an accumulation effect, it is necessary to establish a complete environmental safety control system for heavy metals. Meanwhile, using three pozzolanic activity testing methods, the activity index of SP is measured to be 99 %–114 %, among which Henan and Hebei are the highest. On this basis, combined with the free calcium oxide content in slag powder, the shrinkage laws of slag powder mortar specimens at the ages of 4 d, 7 d and 14 d were further investigated. Moreover, the quadratic polynomial regression model can more accurately fit the nonlinear evolution trend of the shrinkage, and its coefficient of determination (R²) is better than that of linear regression, with the highest reaching 0.969. This research can provide a good basic technical support and reference for the domestic building materials industry.