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Abstract: In the semiconductor manufacturing industry, the dynamic model of a controlled object is usually obtained from a frequency-sweep method before motion control. However, the existing isolator cannot properly isolate the disturbance of the inertial force on the platform base during frequency sweeping (the frequency is between 0 Hz and the natural frequency). In this paper, an adjustable anti-resonance frequency controller of a dual-stage actuation semi-active vibration isolation system (DSA-SAVIS) is proposed. This system has a significant anti-resonance characteristic, that is, the vibration amplitude can drop to nearly zero at a particular frequency, which is called the anti-resonance frequency. The proposed controller is designed to add an adjustable anti-resonance frequency to fully utilize this unique anti-resonance characteristic. The experiment results show that the closed-loop transmissibility is less than -15dB from 0 to the initial anti-resonance frequency. Furthermore, it is less than -30dB around an added anti-resonance frequency which can be adjusted from 0 Hz to the initial anti-resonance frequency by changing the parameters of the proposed controller. With the proposed controller, the disturbance amplitude of the payload decays from 4mm/s to 0.5 mm/s with a reduction of 87.5% for the impulse disturbance applied to the platform base. Simultaneously, the system can adjust the anti-resonance frequency point in real time by tracking the frequency-sweep disturbance and achieve good vibration isolation performance. This indicates that the DSA-SAVIS and proposed controller can be applied in the guarantee of an ultra-low vibration environment especially at frequency sweeping in the semiconductor manufacturing industry.