Abstract: In order to comprehensively utilize the industrial waste residue, a concrete was made of a blas-t furnace slag taken as coarse and fine aggregate. After 24 h oven drying at 110 e, the concrete was treated for 3 h under constant temperatures of 300, 500 and 700 e respectively. The study was conducted to measure the impacts of sand percentage (SP), maximum particle size of coarse aggregate, water-cement ratio and cement quantity, on the thermo-stability of slagbased aggregate concrete. The result indicates: at 300 e the relative compression strength(RCS) is above 100%, at 500 e, the RCS is between 57%~ 86%, at 700 e, the RCS is between 22% ~ 58%. More SP value, smaller max imum particle size of coarse aggregate, lower water-cement ratio and the less cement quantity are beneficial to enhance the thermostability of the concrete; with slag-based aggregate, a concrete can be made with thermo resistance at 500 e.