Ocean electric field detection technology is in the ascendant. Traditional Ag/AgCl electrodes are costly and require stringent storage and transportation conditions. And carbon fiber electrodes are susceptible to environmental changes that affect signal response. To address these inherent challenges in practical applications, this study prepares ocean electric field electrodes based on carbon paper. Through electrochemical modification to adjust the number and proportion of oxygen-containing functional groups, we improve the electric field response performance of carbon paper electrode. Experimental findings reveal that electrochemical oxidation (EO)/reduction (ER) introduces a large number of oxygen-containing functional groups onto the electrode surface, altering the surface functional groups and improving surface polarity and hydrophilicity. As the proportion of electrochemical oxidation time gradually increases, EO8 exhibits superior distribution ratios and uniformity of oxygen-containing functional groups. Electrochemical test results indicate that EO8 has a specific capacitance of 1.678 F/g. At 0.01 Hz, the electrochemical impedance of EO8 is 2 117.60 Ω·cm², with the charge transfer resistance of 1 709.60 Ω·cm². These results demonstrate the significant improvement in electrochemical performance of EO8. Electric field response tests show that the potential drift of the EO8 paired electrodes is only 2.12 mV/d, with electrode self-noise reduces to 14 nV/rt Hz@1 Hz. Moreover, the EO8 paired electrodes can effectively respond to low-frequency weak electric field signals of 10 mV and 10 mHz. Compared to blank carbon paper electrodes, the sensitivity and accuracy of modified electrodes are significantly enhanced. Thus, carbon paper becomes promising candidate materials for ocean electric field electrodes.