Abstract: Besides temperature and pressure, conductivity is among the most relevant parameters characterizing the physical state of seawater. By analyzing distribution and variability of water electrical conductivity, people can research on electromagnetic characteristics and chemical composition of seawater. In this paper, a method for obtaining the distribution information of sea surface conductivity with HF surface wave radar is studied. Based on the ground wave propagation attenuation characteristics on the sea surface, the ground wave attenuation factors with different observing patches are analyzed. Then the model of the sea surface conductivity and the ground wave attenuation factor is built. After that, the algorithm of sea surface conductivity inversion based on HF surface wave radar system is presented. The experiment results indicate that this method is feasible.