The northwest of China is experiencing a severe water deficit and salinization of the land. Pentaerythritol diacrylate (PEDA) was developed as a new cross-linking agent, and Polyacrylic acid/ Pentaerythritol diacrylate (PAA/PEDA) was created by free radical polymerization utilizing acrylic acid as the monomer, to enhance the water retention and salt isolation qualities of soil. Infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis were used to determine the structure, morphology, and thermal stability of the improved SPA. Under ideal synthesis circumstances, the water absorbency of SPA in deionized water, tap water, and NaCl solution (0.9 wt%) was 501 g/g, 150 g/g, and 58 g/g, respectively. The water retention, reswelling, fertilizer retentio, anti-leakage, and salt isolation properties of PAA/PEDA at different temperatures under optimal conditions were investigated. The results showed that the PAA/PEDA material had the best water retention at room temperature; the addition of 0.8% PAA/PEDA material reduced the water infiltration rate by 86% compared with the blank control group; The addition of 0.4% PAA/PEDA material showed a lower salinity trend than the control, and the PAA/PEDA material had a hindering effect on the upward movement of salts in the soil.