In view of the salinization problem caused by water scarcity and high evaporation in western China, a new water-soluble water-retaining agent is selected for the ecological improvement of saline soils, aiming to enhance their water retention capacity. This paper carries out indoor water retention tests and selects the appropriate concentration of new water-soluble water-retaining agent to be applied in field tests according to the water retention test results. Meanwhile, the soil moisture, temperature and conductivity changes are monitored and analyzed to investigate the effect of the new water-soluble water-retention agent on the water retention capacity of saline soils. The result shows show that:(1) the new type of water-soluble water retaining solution reacts with soil particles to form a milky elastic mucosa, which makes part of the water to be stored between the membrane structure and soil particles, and the existence of the membrane structure also changes the time of water movement upward and delays the evaporation effect; (2) when the concentration of water retaining solution is 0.5%, the water retention capacity of the soil is significantly improved, and, the soil water retention capacity is gradually enhanced with the concentration of water retaining solution; (3) The use of new water-soluble water retaining solution can improve the temperature and humidity of soil in salinized areas to a certain extent, reduce the salt separation on the surface of soil layer. The results can provide some references for improving soil water conservation in saline soil area under strong evaporation.