The invention relates to a three-phase linkage transmission gear and a high-voltage switch. The high-voltage switch comprises a three-phase switch and the three-phase linkage transmission gear. The three-phase switch comprises draw bars and three crank arms. The three-phase linkage transmission gear comprises a first connecting rod assembly and a second connecting rod assembly. The first connecting rod assembly and the second connecting rod assembly are sequentially connected with the three crank arms, connectors are arranged at two ends of each connecting rod assembly, the lengths of the two connecting rod assemblies can be adjusted, hinge holes for being hinged to the first crank arm and the second crank arm are respectively formed in the two connectors of the first connecting rod assembly, hinge holes for being hinged to the third crank arm are formed in one connector of the second connecting rod assembly, hinge holes for being hinged to the second connecting rod assembly are formed in the middle connector of the first connecting rod assembly, the first connecting rod assembly and the second connecting rod assembly are collinear with each other, and hinged points of the first connecting rod assembly and the second crank arm are positioned on a straight line where the first connecting rod assembly and the second connecting rod assembly are located. The three-phase linkage transmission gear and the high-voltage switch have the advantages that only small spaces are occupied by connecting rods, only low torsional force is applied to hinged shafts, and accordingly the service lives of the hinged shafts can be prolonged.