Recently, a mechanism for the High-Static-Low-Dynamic Stiffness (HSLDS) magnetic vibration isolator was introduced to overcome the fundamental limitation of a linear vibration isolator. The mechanism has a particularly useful property whereby the stiffness of the isolator is large enough to hold the weight of a load, but produces much softer stiffness when it responds to a dynamic motion. That is, the HSLDS magnetic vibration isolator shows highly nonlinear vibration isolation characteristic depending on the system parameters as well as the amplitude of base excitation. In this paper, the isolation performance of the HSLDS magnetic vibration isolator is examined both analytically and experimentally by considering both the key system parameter and the excitation amplitude of the base. The results show that the vibration isolation performance improves as the amplitude of base excitation increases. It was also found that the suggested key system parameter has an important role in the design of a practical system, and guarantees the minimum isolation performance regardless of the excitation amplitude.