To explore the corrosion of Q235 steel in sand containing a simulated haze aqueous solution (HA solution) under a natural air-dried state, the effect of moisture (age) on the corrosion of Q235 steel in sand was comprehensively studied by EIS, polarization curve, SEM, EDS and XPS. The physical and chemical properties of the sand showed that the sand containing the HA solution was basically neutral under natural air drying, and the temperature was around 20 °C. After 14 days, the moisture content gradually decreased from 30% to 0%, and the salinity decreased from 1.26% to 0.04%. With the increase in age, the Eocp gradually positively skews, indicating the corrosion kinetics of the Q235 steel decrease. The impedance spectra showed that in the frequency of 10−2–103 Hz, the impedance spectra exhibited a flat capacitive loop, and the corrosion of Q235 steel was the strongest in the sand containing HA solution on the 8 d. The polarization curves showed that with increasing age, the degree of corrosion of Q235 steel changed from medium or above to slight corrosion in the sand containing HA solution. The pitting characteristics of anode branch for polarization curve also indicate the faster corrosion kinetics of Q235 steel in the early age (1–5 d). The corrosion current density Io first increased and then decreased, and the highest value was 3.44 × 10−5 A/cm2 at 6 d. The average corrosion rate was 0.1629 mm/a. HA solution accelerates the corrosion of Q235 steel in sand without HA solution (average corrosion rate, 1.51 × 10−2 mm/a). A large amount of brown-yellow corrosion products (iron oxides, about 70–200 μm) presented on the surface of the Q235 steel. The corrosion of Q235 steel belonged to local corrosion, and the corrosion pits were connected to form a large dimple-like area. The HA solution and the porous structure of sand jointly affect the electrochemical corrosion of Q235 steel.