The invention discloses a fixed contact assembly having a zero-sequence current transformer. The fixed contact assembly comprises a mounting seat and a base above the mounting seat, wherein an assembly body is fixedly mounted on the base; two symmetrically disposed positioning slots are disposed downwardly on the top of the mounting seat; two symmetrically disposed positioning rods are fixedly mounted on the bottom of the base; first triangular blocks are fixedly mounted on the sides of the two positioning rods away from each other; the positioning rods and the first triangular blocks are movably installed in the corresponding positioning slots; first grooves are formed in the inner walls of the sides of the two positioning slot away from each other; sliding plates are slidably mounted inthe first grooves; second triangular blocks are fixedly mounted on the sides of the two sliding plates close to each other, extend into the positioning slots and match the corresponding first triangular blocks; the bottom inner walls of the first grooves are provided with stopping slots. The fixed contact assembly can conveniently install the base, and is simple in structure and is convenient to operate.