This paper focuses on the modeling and step-change control strategy of high-temperature superconducting (HTS) maglev trains. Utilizing electromagnetic induction, HTS maglev trains achieve levitation through repulsion between superconducting materials and permanent magnets. The train is propelled by a long-stator linear motor, which requires a segmented power supply to reduce energy loss. A critical challenge lies in maintaining stable traction force during inverter switching across stator segments. To address this, the paper proposes a dual-inverter step-change control method. The modeling of the linear motor is carried out under ideal conditions, and the corresponding voltage, flux, and force equations are derived. A step-change control flowchart is developed based on the switching logic of adjacent stator segments. Simulation is performed using MATLAB/Simulink, integrating the derived motor model and control strategy. The simulation results demonstrate that the proposed method effectively minimizes current fluctuations and traction force loss during segment transitions. This research provides practical insights for improving operational stability and energy efficiency in future HTS maglev systems.