In order to explore the effects of sodium salt content on the stability of silty engineering slope in marine saline-alkali land, limit moisture content and shear strength experiments were carried out to investigate the influence of Na⁺ content on the soil mechanics parameters including limiting moisture content, shear strength and other parameters. Moreover, combined with the calculation of the infinite slope safety factor, the influence of soil Na⁺ content on slope stability under different saturation conditions was defined. The results showed that with the increasing of Na⁺ content, the plastic limit of soil sample increased slowly, while the liquid limit decreased. In addition, average cohesion and average internal friction angle both decreased with the increasing of Na⁺ content. For the same soil texture, the slope safety factor (FS) decreased with the increasing of Na⁺ content when the soil saturation was constant. When the Na⁺ content was constant, the greater the soil saturation, the less the FS was, and the FS reached the minimum value when soil was fully saturated. The higher the soil saturation, the greater the decrease amplitude of FS with the increasing of Na⁺ content.