Suspended droplets in oil experience pronounced polarization and deformation under the influence of an external electric field. Traditional grid-based methods face limitations in capturing the intricate local features of the droplet interface, while gridless particle methods offer advantages with respect to capturing the droplet interface. The present study establishes a coupled model, consisting of smoothed particle hydrodynamics (SPH) and finite volume method (FVM). The nodal electric field force was solved using the FVM and transferred to SPH particles. Thereafter, the SPH method calculates the forces and updates the position information of particle. The coupling of the electric field and flow field enhances the precision of interface capture and numerical simulation. The numerical findings were compared and validated using published experimental data. Based on this, the study examines the aggregation behavior of droplets under a rectangular wave electric field, illustrating the process of droplet aggregation and analyzing the variation of interfacial tension. The results show that two droplets approach each other in an oscillating manner under a rectangular wave electric field, with interfacial tension hindering droplet approach and promoting the fusion process.