The invention discloses a mechanical decoupling single-hole surgery robot rapid replacement mechanism with a prismatic joint. The mechanism comprises a first joint driving mechanism, a second joint driving mechanism, a third joint driving mechanism, a fourth joint driving mechanism, a fifth joint driving mechanism, a sixth joint driving mechanism, a seventh joint driving mechanism, an eighth jointdriving mechanism, a base shell, a base outer cover, a connector and a locking mechanism. A surgical instrument rapid replacement mechanism is provided with a mechanical decoupling mechanism and completely solves the problem of mutual motion coupling generated when joints of surgical instrument executing mechanisms swing and rotate, the mechanical decoupling mechanism is mounted on the base, structure design of the surgical instrument executing mechanisms can be simplified, and mass production of the surgical instrument executing mechanisms is facilitated. The mechanical decoupling rapid replacement mechanism with the prismatic joint for a single-hole surgery robot has the advantages of convenience in disassembly and assembly, easiness in adjustment, accuracy in positioning, high stiffness, reasonable layout, small size and light weight.