【Objective】Soil salinization is one of the most important environmental problems that restrict the ecological system and the sustainable development of agriculture in the Yellow River delta. Composed mainly of silt and fine sand the soil is stronger in capillary water action, turning groundwater into the main factor affecting migration, accumulation and release of salt in soil body. To study relationships between soil salinity and groundwater will sure be of important theoretical value and practical significance to amelioration of the saline alkali soil and control of secondary salinization of the soil in the Yellow River Delta. 【Method】In order to study the relationship between salt accumulation in topsoil and groundwater characteristics and to monitor in-situ variation of soil salt content and groundwater table in the Yellow River Delta, four sections were laid out and a total of 20 wells set up by taking into full consideration factors like hydrogeological features, soil salinization status, topography, land use and human activities. Groundwater tables in the wells were measured, and water samples from the wells and topsoil (0~15cm) samples in the locations of the wells were collected in February, May, August and November, 2013 for analysis of salt content and characteristics of the groundwater. Groundwater tables were measured, and samples of the groundwater and topsoil (0~15 cm) were collected from the wells and the fields near the wells, separately, in February, May, August, and November 2013, for analysis of soil salt content and characteristics of the groundwater. Grey correlation analysis of the obtained data was performed to quantitatively analyze relationships of groundwater table with EC, pH, and ion content (Ca²⁺, Mg²⁺, K⁺, Na⁺, CO₃²⁻, HCO₃⁻, Cl- and SO₄²⁻) of the water relative to season. 【Result】Results show that soil salt varied in the range of 3.90~6.31 g kg^-1 in content, in the topsoils and of 2.54~3.44 g kg^-1 in the subsoil both belonging to the category of medium or higher in salinization degree; Groundwater tables were all rather high, fluctuating in the range of 1.16~1.71 m; and the anion in the groundwater was dominated with Cl^-1, while the cation with Na⁺, accounting in total for 65% of the total of ions. Correlation analysis shows that the relationships of the groundwater characteristics with salt content in the topsoil varied from index characteristics and with time as well. On the whole, salt accumulation in the surface soil was closely related to EC, Na⁺ and Cl^- in the groundwater, but not so to pH, CO₃²⁻and HCO₃⁻. 【Conclusion】To control and manage soil salinization in the Yellow River Delta, it is essential to intensify control of EC, Na⁺ and Cl^- in the groundwater of the region.