Efficient oil-water separation is essential for treating produced fluids in petroleum engineering. This study investigates performance enhancement in hydrocyclones coupled with particles through theoretical analysis, visualization experiments, and numerical simulations. A critical model for oil droplet-particle collisions was established, revealing that smaller particle diameter, larger rotational radius, and smaller contact angle favor stable adsorption. Visualization experiments confirmed that particles promote droplet migration toward the hydrocyclone center, forming stable droplet-particle complexes at low rotational speeds while rebound dominates at higher speeds. A discrete element model based on the Johnson-Kendall-Roberts (JKR) adhesion theory was developed and validated, achieving a repose angle error of only 0.24%. Numerical results demonstrate that oleophilic particles significantly enhance droplet adhesion and improve overall separation efficiency by 8.19 percentage points, achieving 79.23% efficiency for 67 μm droplets (29.68 points higher than conventional hydrocyclones). These findings offer theoretical and practical support for optimizing and applying hydrocyclones coupled with particles in oilfield fluid treatment.