The advantages of levitation and guidance integration make the high-temperature superconducting (HTS) maglev system have great potential in the field of high-speed transportation. However, due to the influence of some factors such as the Dewar (a low temperature thermostat for superconductors) vacuum increases and magnetic field irregularity, the levitation force will decline and working height will drop. To solve the problems, this paper proposes a compensation method based on electromagnetic auxiliary device. Firstly, the thought and purpose of this method are explained in detail. Secondly, the effectiveness of levitation force compensation is verified by experiment. Then, electromagnetic simulation model is established and its correctness is verified by comparing simulation results and experimental data. Finally, dynamic simulation is conducted based on the verified model to study the vibration characteristics of Dewar system. The results show that the auxiliary device can compensate the levitation force and suppress vibration well. Meanwhile, comparing with the field cooling height (FCH) at 20 mm and 30 mm, the compensation effect of former is better than latter, but the overall maximum levitation force of latter is higher than former. This research provides an economical and effective way to achieve the levitation force compensation of HTS maglev system. Furthermore, the electromagnetic auxiliary device is an active energy input port, providing the possibility for the active control of HTS system. It is expected to provide reference for future practice in relevant application fields.