The locomotive wheelsets configured with high-power AC traction motors are very prone to slip under poor friction conditions, which usually impair traction/braking efficiency. To avoid the adverse consequence caused by the conspicuous slipping behaviors of wheels, the antislip control modules are consequently equipped on high-power locomotives. This paper presents an advanced antislip control algorithm for heavy-haul locomotives traveling by complex wheel/rail friction conditions. The proposed antislip control model is implemented in a three-dimensional (3D) heavy-haul train-track coupled dynamics model, in which the real-time estimation of wheel/rail adhesion conditions and relevant optimization adjustment of control threshold values are considered. The wheel/rail dynamic interactions of the heavy-haul locomotive under traction/braking conditions and multifarious friction conditions are investigated. The control effects of the antislip controllers with changeable and constant threshold values are compared. It is shown that the traction/braking loads and friction conditions have a significant effect on wheel/rail interactions. The optimal traction/braking efficiency can be realized by adopting the antislip controller with alterable threshold values.