【Objective】 Water and nutrients are essential elements plants need for growth. So it is very important to improve soil moisture regime and crop fertilizer utilization efficiency in agricultural production. The purpose of this study is to investigate effects of a home-made salt-tolerant water retaining polymer on leaching loss of potassium and growth of maize, and determine roles of the polymer in water retention and soil nutrient conservation in sand, in an attempt to provide certain technical support for application of the polymer in the arid area. 【Method】 In this study, a pot experiment was carried out using sand instead of soil to explore effects of the polymer on leaching of potassium fertilizer and growth of maize of two consecutive seasons. The part for leaching of potassium was designed to have four treatments, in terms of application rate of the polymer, i.e. 0 g·kg^-1 (blank), 0.5 g·kg^-1, 1.0 g·kg^-1 and 2.0 g·kg^-1, and the part for maize growth also had four treatments in terms of application rate of the polymer, too, i.e. 0 g·kg^-1 (blank), 0.5 g·kg^-1, 1.0 g·kg^-1 and 1.5 g·kg^-1. At the same time, all the treatments were subjected two levels of soil water content separately, that is normal and drought. The second crop of maize was planted after the harvest of the first in the normal group. Content of potassium in leachate from each pot was determined and plant height, stem diameter, dry weight, fresh weight, maximum leaf area and absorptive amount of N, P and K of the maize were measured. 【Result】 All the findings of the experiment demonstrate that the polymer helps reduce leaching loss of potassium fertilizer in sandy soil. Comparing with the control, the treatment amended with 0.5 g·kg^-1 or 1.0 g·kg^-1 polymer was 12.96% or 47.85%, respectively, lower in potassium leaching loss. In the treatment amended with 0.5 g·kg^-1, 1.0 g·kg^-1 and 1.5 g·kg^-1, the crop survived 12 days, 19 days and 30 days longer, respectively, in the drought group, and the crop of the first harvest was 8.83%, 19.63% and 22.39%, respectively, higher in N absorptive amount, 29.31%, 30.19% and 52.38% higher in P absorptive amount and 11.61%, 18.12% and 20.72% in K absorptive amount, and the crop of the second harvest was 55.50%, 117.1% and 143.7%, higher in N absorptive amount, 77.12%, 161.3% and 156.5% higher in P absorptive amount and 55.42%, 74.13% and 84.33% higher in K absorptive amount, respectively. 【Conclusion】 All the findings in this experiment demonstrate that application of the home-made salt-tolerant water detaining polymers in arid and even desert areas could significantly reduce nutrient loss and improve soil water regime.