Over years of planting，soil-to-sand ratio and the contents of soil salt and water in the sand fields changed substantially，and the degradation of the sand lands accelerated． This study addressed the mechanism of water-salt variation and summarized the causes of degradation，providing the basis for sand field maintenance． The results show that the practice of cultivation increased soil-to-sand ratio，however，reduced soil water holding capacity，soil water storage，and soil anti-evaporation capacity． The water-salt variation of the sand land was closely related to the length of planting years，gravel cover thickness，diameter of the gravels，location of gravel on the surface soil，and water table depth． To some extent，the water-salt variation has led to the degradation of the sand fields．