The influence of air-entraining agent, and the enhancement effect of one weak alkaline activator-sodium lactate on the salt frost resistance of supersulfated cement concrete were systematically investigated. Specifically, the surface spalling mass and relative dynamic elastic modulus of ultrasonic of concrete after different cycles of salt freezing were periodically tested, and the air-void structure characteristic was characterized. The results indicate that adding air-entraining agent effectively improves the salt frost resistance of supersulfated cement concrete but with the loss of strength, and the compound addition of sodium lactate avoids strength loss. Adding 0.3% (mass fraction) air-entraining agent of cementitious material, the spalling mass is only 919.7 g/m2, which is 36.8% lower than that of the reference group, and the relative dynamic elastic modulus of ultrasonic is not significantly reduced. The addition of air-entraining agent ameliorates the air-void structure of supersulfated cement concrete, including the reduce of internal pore spacing ecoefficiency and proportion of pore with string length greater than 100 μm. This can slow down the development rate of internal microcracks and delay the failure under freeze-thaw cycles. In addition, sodium lactate promotes the hydration of supersulfated cement and enhances the salt frost resistance of concrete. However, the enhancement effect mainly appears in the late test period. Meanwhile, sodium lactate has little influence on the air-void structure parameters of concrete (28 d).