In order to solve the problem of huge freedom of movement, modeling difficulty and the long calculation time of the long and heavy haul train, and considering the dynamic braking characteristics of the air brake, a new method named Circular-Variable Modeling and Calculation Method and combined with the air brake dynamic braking characteristics which based on the actual air flow theory have been used in this thesis, and a three dimensional coupling dynamics model of the heavy haul train was set up, the brake wave during the process of the braking was revealed, and the longitudinal and lateral coupler force and dynamic performances of heavy haul train like axle-wheel lateral force, the wheel-rail lateral force, derailment coefficient and wheel load reducing rate while braking were systematic analyzed, and the couplers and dynamic performances of the routine braking and emergency braking were compared. From the calculation, it can be known that, the longitudinal and lateral coupler force of the emergency brake is much larger than the routine brake, the axle-wheel lateral force, the wheel-rail lateral force and the derailment coefficient of routine braking is greater than emergency braking except for the rear part vehicles of the train where the longitudinal impluse is very large while emergency braking, the wheel load reduction rate while emergency braking is smaller than the routine brake, but the extent of change is larger than the routine brake.