Aiming at the demand of seismic protection of free-standing objects, a pendulum isolation device based on universal balls was developed. The structural characteristics and operation principle were introduced, and the design of an isolation device for protecting a pagoda could serve as a case study. Then the finite element software was used to analyze the bearing capacity between the universal ball and the disc. The accuracy of the damping mechanism analysis model was verified by tests. The isolation effect of the device under the eight-degree extremely rare earthquakes was analyzed by time history method, and was compared with the traditional friction pendulum. The results show that the isolation device not only has simple structure and reliable performance, but also has the characteristics of low friction coefficient, small acceleration threshold for triggering slip and flexibly adjustable damping mechanism. The carrying capacity of the node-to-surface contact can meet the design requirement. By means of viscous damper at one end, the damping mechanism shows obvious velocity correlation, and damping force increases with the increase of velocity. The device can achieve the isolation target while satisfying the displacement limit. Compared with the traditional type, when the displacement and acceleration response are limited, the device can achieve better comprehensive isolation effect under various seismic conditions by reasonably adjusting parameters of the damping mechanism.