Based on the static analysis, dynamic model of C,80, heavy haul train was built to investigate the influence of partial load on running safety of heavy haul train. Under the different partial load condition, the derailment coefficient and the wheel load reduction rate were calculated when the train passed the curve. The analysis results show that with the increase of partial load, the running safety of the train is getting worse. Longitudinal partial load has main effect on the derailment coefficient of wheel, and lateral partial load has main effect on the rate of wheel load reduction. With the increase of lateral partial load, the rate of wheel load reduction increases obviously, so the lateral partial load should be strictly controlled.