Asphaltenes play an important role in stabilizing water-in-oil (W/O) emulsions and have significant effects on droplet coalescence and electrodehydration efficiency, but their fundamental mechanisms remain unclear. This paper comprehensively considers the influence of asphaltenes on droplet coalescence and finds that in the macroscopic electrodehydration process, as asphaltene concentration increases, the electrodehydration efficiency of crude oil emulsions decreases significantly. When asphaltene concentration exceeds 1 wt.%, the water content increases sharply, indicating a dramatic decline in dehydration efficiency. Microscopic experiments were conducted to investigate the macroscopic phenomena, and the results show that with increasing asphaltene concentration, more asphaltenes adsorb onto the droplet surface, enhancing the viscoelasticity of the liquid film, and droplet coalescence does not occur. To understand the mechanism of asphaltene influence on droplet coalescence, molecular dynamics simulations were employed to elucidate the effect of asphaltenes on droplet deformation under electric field conditions. The results indicate that under electric field action, strong interactions between asphaltene molecules and water molecules cause asphaltene molecules to adsorb on the droplet surface, and with increasing asphaltene concentration, droplet deformation is further hindered. The research findings provide a scientific basis for in-depth understanding of the role of asphaltenes in crude oil electrodehydration processes.