[Objective] To explore the characteristics of water evaporation in soil cracks treated by different backfill techniques. [Methods] The soil was collected from the surface of the west dump of Haizhou open-pit mine, and the soil cracks were simulated by backfilling treatment and analyzed by simulated evaporation test in the laboratory. [Results] The daily evaporation of cracks showed obvious three-stage evaporation rule in the test, and different backfilling treatments had little effect on the daily evaporation of cracks; With the increase of crack width, the cumulative evaporation of cracks increases, and backfill treatment can effectively reduce the cumulative evaporation of cracks. The cumulative evaporation of cracks with a backfilling ratio of 1:1 is the minimum value under the same group of cracks backfilling. The appearance of cracks will lead to the reduction of soil moisture content, but backfill treatment can improve the moisture content of cracks, and the water content of treatment 1 with backfilling ratio of 1:1 is the highest value of the three groups of cracks, with an average value of 29.74%; The increase of crack width also has an impact on the evaporative water-loss ratio, and the backfill treatment can reduce the evaporative water-loss ratio, and the backfill ratio of 1:1 treatment 1 has the best performance in reducing the evaporative water-loss ratio. [Conclusion] The existence of cracks has an effect on the daily evaporation, cumulative evaporation, water content and evaporation water loss ratio of cracks, and the 1:1 backfill ratio of treatment 1 has the best performance in the study of water evaporation of soil cracks in the dump.