The electrical conductivity (EC) of soils is a crucial parameter in geotechnical engineering, providing valuable insights into soil properties such as mineralogy, moisture content, and particle distribution. This study explores the electrical conductivity of fine-grained soils and its application in soil classification. A series-parallel structure-oriented model for electrical conductivity is proposed, incorporating parameters such as diffuse double layer (DDL) effects, pore water salinity, and temperature influence. Experimental validation confirms that EC measurements can accurately predict soil classification attributes such as particle size distribution (PSD), liquid limit (LL), and plastic limit (PL). The proposed approach provides a cost-effective and rapid alternative to conventional geotechnical testing methods.