Due to the large amount of dredged sand produced by dredging in the lower reaches of the Yangtze River, the resource utilization of dredged sand has been given attention. The mortar was prepared by partially replacing manufactured sand with dredged sand, and the influence of different static stop time on the characteristics of dredged sand mortar was studied, the compressive strength at different ages was tested, through X-ray diffraction, scanning electron microscopy, and mercury pressing technology, the micro characteristics of different static stop time different dredged sand replacement rate mortar. The results show that with the increase of static stop time, the 90 d compressive strength increases gradually, and the impermeability is also significantly improved; The compressive strength of mortar increases with the addition of dredged sand, and increases first and then decreases with the increase of replacement rate of dredged sand; The compressive strength of dredged sand mortar has a great relationship with the replacement rate of dredged sand, and its influence degree is related to the static stop time. The dredged sand has a prominent strengthening effect on the low static stop time; dredged sand can effectively improve the problems of pore structure coarsening and pore enlargement caused by steam curing. Appropriate replacement rate of dredged sand has obvious improvement effect on the performance of steam curing mortar.