With the improvement of water quality standards and detection technology, the control of new pollutants has gradually become a research hotspot. The activation ability of divalent manganese to peroxymonosulfate (PMS) was improved by introducing an electric field, and the E-Mn2+-PMS synergistic process was constructed to remove the refractory organic pollutant diclofenac (DCF) in water. Firstly, the effects of current density, PMS concentration, Mn2+ concentration, solution pH value and water matrix (NO3-、Cl-、HA) on the removal of DCF in water were discussed, respectively. The results indicated that the synergy indices of the E-Mn2+-PMS process was 10.88 within 20 min of reaction, and its reaction rate constant was 19.250×10-2 min-1. The mineralization rate of DCF was 67.4% in 180 min, under the experimental conditions: current density was 11.42 mA cm-2, PMS concentration was 1 mM and Mn2+ concentration was 150 μM. Acidic conditions facilitated the removal of DCF, and the optimal pH value was 3. NO3- had almost no effect on the removal of DCF, and Cl- and HA promoted the removal of DCF significantly. Subsequently, it was demonstrated by radical scavenger experiment, electron paramagnetic resonance (EPR) tests, and analysis of manganese intermediate valence substances. The non-radical pathways (Mn(III) oxidation and 1O2 oxidation) dominated in the E-Mn2+-PMS process. Compared with Mn2+-PMS process, the amorphous MnO2 generated in situ under electric field conditions could quickly activate PMS to produce 1O2, achieving efficient removal of pollutants.