The invention discloses an eddy-current damping zero-stiffness vibration isolator with an angular decoupling function by the aid of a sliding joint bearing, and belongs to the technical field of precision vibration isolation. Space between a sleeve of a vibration isolator body and a lower mounting plate and space between a piston barrel and the sleeve are respectively lubricated and supported by air floatation planes, eddy-current dampers are used for attenuating vibration energy and improving the positioning stability, the degree of freedom of angular movement between an upper mounting plate and the lower mounting plate is decoupled by the sliding joint bearing, and voice coil motors, displacement sensors, limit switches, a controller and a driver form a position closed-loop feedback control system to precisely control relative positions of the upper mounting plate and the lower mounting plate. The eddy-current damping zero-stiffness vibration isolator has the advantages of zero stiffness in perpendicular and horizontal directions, high positioning precision, the angular decoupling function, capability of acquiring extremely low natural frequency and outstanding low-frequency / ultra-low-frequency vibration isolation performance, and accordingly effectively realizes high-performance vibration isolation for ultra-precision measuring instruments and processing equipment, and particularly for step-scan lithography machines.