Abstract: In order to improve the deterioration of the strength of alkali slag-cement cured sludge caused by alkali slag doping, the industrial waste slag is introduced to improve its mechanical properties. Firstly, the deterioration effects of alkali slag on the strength of cement-cured sludge are analyzed through the large dosage alkali slag-cement-cured sludge tests. Subsequently, the unconfined compressive strength tests and SEM tests on six single industrial waste slag-alkali slag-cement-cured sludges are carried out. The results show that the improvement effects of blast furnace slag are better in the short age period, and those of calcium carbide slag on the unconfined compressive strength of alkali slag-cement-cured sludge are the best in the long age period. By analyzing the scanning electron microscope results, the micro-mechanisms of the cured sludge of blast furnace slag-alkali slag-cement and calcium carbide slag-alkali slag-cement are clarified. The results can provide a design basis for the curing projects using large dosage of alkali slag to treat dredged sludge.