In this study, an electrocatalytic system was constructed using Ti/RuO₂-IrO₂-SnO₂-Sb as the anode and stainless steel as the cathode, targeting the microalga Heterosigma akashiwo to investigate the inhibition and removal efficiency of the system. The electrochemical performance of the electrodes was studied using electrochemical methods, and the morphology and microstructure of the electrodes were characterized using SEM, XRD, and XPS. The algal inactivation efficiency of the system was explored by varying the electrolysis time, current density, and electrode area. The primary oxidants generated during electrocatalysis were also analyzed. The results indicated that the electrode metal oxides were well overlaid and stable, exhibiting good electrochemical performance. When a voltage was applied for 2 minutes at a current density of 60 mA/cm² and an electrode area of 6 cm², the inactivation rate of microalgae reached 93.5% after 120 minutes. The main oxidants generated during electrocatalytic algal inactivation were identified as HClO/ClO^-, and the total residual oxidants (TRO) exhibited a time-dependent decay, providing sustained oxidizing capacity to the electrocatalytic system. The study demonstrated that the electrocatalytic system effectively inactivated microalgae and maintained a prolonged inactivation effect, offering a potential reference for the treatment of ballast water in ships.