Effect of irrigation water quality on soil chemical characteristics and on crop growth was studied in this work. The salt content and sodium adsorption ratio (SAR) of irrigation water were considered to be two main indexes which were combined in the 16 treatments of irrigation water quality in the experiment. Results showed that salts of irrigation water were accumulated and leached alternately in the soil. When salt content of irrigation water was below 3.0g/L, the salt was kept balanced in soil profile. When the salt content of irrigation water was more than 3.0g/L, the salt was accumulated in the soil, even resulting in the medium secondary salinization. High SAR and high Na₂CO₃ in irrigation water can cause Ca²⁺ and Mg²⁺ to form sediment of CaCO₃ and MgCO₃ to decrease Ca²⁺ and Mg²⁺ concentration and to increase Na⁺ concentration in the soil solution. Thus SSP, SDR and SAR were risen. As a result ESP increased in the soil. When the SAR of irrigation water was more than 14, and the salt content was more than 3.0g/L or 4.0g/L, the growth and yield of soybean and wheat were influenced, a medium or strong soil secondary alkalization occurred.