Purpose <p>To achieve high efficiency of vibration isolation and to conserve the structural stability for the spaceborne satellite camera in the launch phase, design and validation of the whole-spacecraft vibration isolator with quasi-equal strength, high damping and shock protection is presented.</p> Methods <p>Metal frame structure model of the isolator is established based on equal strength beam theory. The constitutive relation for linear viscoelastic damping material is expressed by five-parameter fractional derivative model. The optimization of constrained damping structure including the damping layer thickness and the number of damping layers is performed by numerical calculation. Finite element analysis and tests for the isolator unit strut are carried out to study the dynamic characteristics of the isolation unit.</p> Results <p>System vibration tests are performed to verify the performance of the whole isolation platform, which is found that the designed vibration isolation system can effectively restrain the transmission of vibration energy.</p> Conclusion <p>The study can shed some light on the design of a passive isolator with quasi-equal strength and high damping.</p>