In order to maintain a good isolation performance of the isolator under low amplitude disturbance. the design method of an hourglass-type electromagnetic isolator with high electromechanical coupling performance is proposed in this paper. Combining a suboptimal Bang-bang control algorithm, the theoretical modeling and performance simulation of the isolator are also completed. The results show that the displacement amplitude at the resonance peak can be decreased by 62.64% when the maximum active force is 1.0 N under the excitation of sinusoidal displacement, and the control effect becomes better with the increase of maximum active force. Also, the root of mean square(RMS) values of output displacement can be decreased by 49.12% and 69.29% when the maximum active forces are 0.5 N and 1.0 N under the random excitation, respectively. The presented electromagnetic isolator has good vibration isolation effect under the active closed-loop control. Compared with the traditional electromagnetic isolator, the isolator has the advantages of not needing additional spring and small control current.