The invention discloses a ballast smoothing system for a ballast hopper car. The ballast smoothing system comprises a ballast smoothing steel mechanism, a wind control system, an upper transmission shaft mechanism, a lower transmission shaft mechanism, a hand brake mechanism, a control lever mechanism and a safety jaw mechanism. The ballast smoothing system is applied to a car body of the ballast hopper car; ballast paving or circuit maintaining of the hopper car is manually or automatically completed by virtue of a series of mechanical actions, so that the ballast smoothing system is controlled pneumatically or manually to lift, and the ballast smoothing height is adjustable; during ballast unloading, ballast, exceeding a rail surface, inside and outside the rail is smoothed, so that the function of smoothing the ballast while unloading the ballast is achieved, and engine-driven use at different loading and unloading positions can be realized. The operation efficiency of the ballast hopper car is improved, operation safety and stability is guaranteed, vehicle derailment caused by ballast accumulation is effectively avoided, the smoothed ballast is attractive in model, labor cost is saved, labor intensity is reduced, working efficiency and operation safety are improved, and the vehicle derailment caused by ballast stacking is effectively avoided.