To evaluate the durability of reinforced concrete structures in marine, salt lakes, etc., this paper explored the characteristics of corrosion-induced cover cracking under combined chloride and sulfate attack by experimental and theoretical analysis. The reinforced concrete specimens were exposed to 5%NaCl, 5%NaCl+5%Na₂SO₄ solutions with electric field for degradation acceleration. The visual appearance of concrete and corrosion of reinforcement under different conditions were compared. Moreover, an accompanied experiment for concrete deterioration was designed in analogy to the cover deterioration, and the mechanical properties of concrete were analyzed. The results showed that in presence of sulfate, the concrete cover appearance altered before cracking; the "white whiskers" under the single chloride solution disappeared while efflorescence existed on the surface of the concrete with sulfate crystallization. Furthermore, the presence of sulfate also extented the time before corrosion-induced cracking. The corrosion level of the reinforcement under the combined attack was lower than that under the single chloride attack, and both were much lower than the predicted value by Faraday′s law. The crack width was linearly correlated with the corrosion level, and the presence of sulfates increased the development of crack width with the corrosion level. Under the electric field, the compressive strength of concrete increased at first and then decreased, while the tensile splitting strength reduced with exposure time. An empirical formula for the tensile strength of deteriorated concrete was proposed. The effect of filling rust products in the cracks was taken into account based on the classic model for corrosion-induced cover cracking. In addition, the effect of sulfate was considered in the tensile strength of concrete and corrosion current density. On these bases, a time prediction model for the corrosion-induced cracking of reinforced concrete under combined attack was established, and the validity of the model was verified.