Time delays (TDs) in the active electromagnetic levitation system significantly affect the running stability and ride comfort of Maglev trains, so it is a critical issue for the technical reform of the speed-up electromagnetically suspended Maglev trains. In this paper, a Smith predictor is employed to compensate for the TD in the electromagnetic levitation system. Simultaneously, a linear active disturbance rejection controller (LADRC) is introduced to estimate and compensate for the errors between the predicted TD and actual TDs as internal disturbances. In this way, we developed a Smith-LADRC levitation controller with the time-delay compensation and active disturbance rejection capabilities. Subsequently, vertical dynamic response of maglev vehicles adopting respectively PID, LADRC, Smith-PID, and Smith-LADRC control algorithm are simulated, and the TD thresholds for stable levitation are compared. The results confirm that the Smith-LADRC levitation controller exhibits the stronger time-delay compensation and anti-disturbance capabilities. Finally, the influence of Smith-LADRC controller parameters on dynamic performances of maglev vehicle is investigated. By balancing the TD stability margin and the fluctuation amplitude of levitation gap, optimal ranges for the controller bandwidth, the observer bandwidth and the controller gain of LADRC are presented.