An improved sliding mode control method based on an extended state observer is proposed to address the problem of control performance degradation of the permanent electric magnetic suspension system caused by unknown perturbations. Firstly， the control experimental platform and theoretical model of the system are analyzed and built for the permanent electric magnetic suspension type magnetic floating ball. Secondly， an extended state observer is introduced to estimate and compensate the system disturbances， and an improved sliding mode control method is designed using an integral sliding mode surface and an improved exponential convergence law to weaken the sliding mode control output jitter and improve the dynamic and static performance of the magnetic floating ball， and to analyze the stability of the system and the approximate range of error convergence with and without the extended state observer to estimate and compensate the disturbances. Finally， the proposed improved sliding mode control method based on the extended state observer， the improved sliding mode control method， the traditional sliding mode control method and the proportional-integral-derivative control method are compared and experimented by the semi-physical joint simulation technique. The theoretical analysis and experimental results show that the proposed improved sliding mode control method based on extended state observer has stronger stability and immunity， more robustness to external magnetic field uptake， and more adaptability to changes and sudden changes in the given signal range. The proposed control method further improves the control performance of the permanent electric magnetic suspension system， and is also a good reference for the control of such nonlinear systems as permanent electric magnetic suspension type magnetic floating ball.