The invention discloses a waterproof structure for a joint of an exterior wall of a fabricated shear wall. The waterproof structure comprises a horizontal joint structure, comprising a water retainingplate, a water retaining rod, a first outer plugging rod, a first pressure reduction chamber and a drainage channel, a first inner plugging rod, a high-strength non-shrinkage grouting material, a grouting sleeve, a schematic vertical reinforcing steel, a lower prefabricated wall, an upper prefabricated wall, a prefabricated laminated board and a cast-in-situ floor layer, four waterproof measuresincluding construction waterproofing, material waterproofing, construction waterproofing and structure waterproofing being provided from the outside to the inside; and a vertical joint structure, comprising a building sealant, a second outer plugging rod, a second inner plugging rod, a positioning protrusion, a positioning recess, a second pressure reduction chamber and a drainage channel, a leftprefabricated wall, a right prefabricated wall, a cast-in-situ connecting portion and a water-break construction, the second outer plugging rod and the second inner plugging rod being positioned according to the positioning protrusion and the positioning recess. The waterproof performance of the exterior wall of the fabricated building can be improved, the construction efficiency can be effectively improved, and the structure is high in applicability and is simple and easy to implement.