[Objective] A new type of high salt-tolerant superabsorbent polymer was prepared by grafting acrylic acid (AA) with chitosan (CTS) and guar gum (GG), with ammonium persulfate (APS) as initiator and N, N'-methylene bisacrylamide (NMBA) as crosslinker. The optimal reaction conditions in the synthetic process were investigated to study the effect of the superabsorbent polymer on the water and nutrient retention in the saline alkali soil.[Methods] The superabsorbent polymer was prepared by aqueous solution polymerization and the optimized reaction conditions were studied based on single factor experiment (degree of neutralization of AA, addition of GG, APS and NMBA). The molecular structure and characteristics of the product were confirmed by fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The absorbent efficiency of product was studied in different saline solutions with different pH value. In addition, the effect of superabsorbent polymer in reforming saline alkali soil was studied by leaching test.[Results] The absorbent efficiency of the product reached the highest when the degree of neutralization of AA was 85%, the amount of GG was 0.2 g, the addition of APS and NMBA were 0.3% and 0.02% of the total monomer, respectively. Under this condition, the absorbent efficiency of product were 1 128 and 185 g/g in deionized water and 0.9% NaCl solution, respectively. The results of FTIR and SEM showed that CTS, GG and AA were involved in the polymerization, and the products had a good spatial network structure and surface morphology. The superabsorbent polymer had a relatively stable absorbent efficiency in the pH value range of 4~10. However, the absorbent efficiency decreased obviously when there were the co-existing cation in the solution, and inhibitory effect of cations on the absorption efficiency was ranked as:Mg²⁺ > Ca²⁺ > Na⁺ > K⁺. And the superabsorbent polymer could not only improve the water holding capacity of the soil but also inhibit the leaching loss of nitrogen and potassium fertilizer.[Conclusion] The superabsorbent polymer prepared in this experiment has better salt tolerant effect and wide range of solution pH value adaptability. The synthetic monomers of the superabsorbent polymer are environmentally friendly, and can effectively reduce the leaching loss of the soil water and fertilizer in the saline-alkali soil.