This study presents the design of a passive cylindrical ring vibration isolator made from a viscoelastic material, with its linear isolation effectiveness evaluated. Nitrile rubber is chosen as a viscoelastic material for the rubber isolators due to its high shear modulus, which enhances energy dissipation and damping in the system. The ring is constrained at the top and bottom, with the bottom part is fixed to the base and the mass positioned on top. The dynamic properties of viscoelastic materials are characterized using a four-parameter fractional order Zener constitutive model. A static load is applied in the diametrical direction to the top of the ring. A finite element model is used to evaluate the displacement transmissibility of the viscoelastic ring under base excitation, considering different geometrical parameters. The results show that the isolator exhibits a relatively low vibration amplitude and a wide range of working frequencies, with its performance significantly influenced by the radius and thickness of the viscoelastic material.