Abstract: Carbon fabric reinforced cementitious matrix (CFRCM) has attracted attention due to its multifunctional properties of impressed current cathodic protection (ICCP), structural strengthening (SS), and structural health monitoring (SHM). However, the current research on the influence mechanism of ICCP on the conductivity properties of seawater sea-sand CFRCM plates is still insufficient. This study conducted simulated ICCP tests on CFRCM plates prepared from normal mortar and seawater sea-sand mortar to investigate the influence and mechanism of conductivity properties of CFRCM under ICCP. The results indicate that the resistance of CFRCM initially shows a linear increase followed by rapid growth with the increase in charge density, and the charge density required for seawater sea-sand mortar CFRCM to enter the rapid growth stage is about 13×10⁵-15×10⁵ C/m², which is greater than the 6×10⁵-8×10⁵ C/m² required for normal mortar CFRCM; The in-homogeneity of the material causes CFRCM to have weak points in the conductivity properties degradation, which will affect the overall resistance change; The seawater sea-sand environment has a positive effect on mitigating the degradation of carbon fiber material properties caused by ICCP. Meanwhile, based on experimental results and electrification parameters, resistance prediction models for CFRCM under ICCP were established. The maximum charge density that seawater sea-sand mortar CFRCM can withstand during service after ICCP electrification was calculated to be 23.21×10⁵ C/m², which is higher than the 17.21×10⁵ C/m² of normal mortar CFRCM, indicating that the chloride-containing environment can effectively prolong the electrical service life of CFRCM. This study lays the foundation for promoting the application of CFRCM with multifunctional properties and simultaneously contributes to the resource utilization of seawater sea-sand.