A two-degree-of-freedom floating vibration isolator (TDOFFVI) based on an anti-resonance mechanism is presented. This isolator has two tunable anti-resonance frequencies capable of attenuating vibrations at one or two frequency excitations simultaneously. A mathematical model of the TDOFFVI is developed. The force transmissibility and the anti-resonance frequencies in conjunction with design parameters are formulated and the optimal design of the TDOFFVI is given. A physical prototype of the TDOFFVI has been designed, built and tested. The experimental results validate the theoretical analysis and show that the TDOFFVI can perform effectively in vibration isolation.