In this paper, the effects of different kinds of sulfate-containing solid wastes on the hydration of Portland cement were studied. The mechanical properties, setting time and linear expansion rate of cement mixed with different kinds of sulfate-containing solid wastes were tested with the change of SO3 content. The influence mechanism of different sulfate-containing solid wastes on the hydration of Portland cement was revealed by means of chemical bound water, XRD and SEM. The results show that with the increase of SO3 content, the flexural strength and compressive strength of cement mortar containing sulfate solid waste increase first and then decrease. The initial setting time and final setting time show an increasing trend, and the increase rate slows down after the SO3 content reaching a certain value. The linear expansion rate continues to increase. The linear expansion rate of cement mixed with various kinds of sulfate-containing solid wastes shows an increasing trend. Due to the different forms of sulfate in different sulfate-containing solid wastes, the dissolution rate of different types of sulfate is also different. The rate and quantity of ettringite (or monosulfoaluminate hydrated) formed by the reaction with tricalcium aluminate in cement are also different, and the degree of hydration at the same age is also different. Therefore, different sulfate-containing solid wastes have different effects on the mechanical properties, setting time and linear expansion rate of cement.