The invention relates to a switch transmission shaft assembly and a three-position isolation switch. The three-position isolation switch comprises the switch transmission shaft assembly, wherein the switch transmission shaft assembly comprises transmission shafts and transmission insulators; shaft sleeve inserts in standstill fit with the transmission shafts are embedded into the transmission insulators; elastic conductors are propped between the adjacent transmission shafts and shaft sleeve inserts; and one end of each elastic conductor and the end surface of the corresponding transmission shaft are in jacking fit and the other end and the corresponding shaft sleeve insert are in jacking fit. The transmission shafts and the shaft sleeve inserts of the three-position isolation switch are in conductive connection through the elastic conductors respectively, the condition that the transmission shafts and the corresponding shaft sleeve inserts are always in effective conductive connection is ensured to form a conductive path, the transmission shafts and the shaft sleeve inserts are located at the same potential and discharging does not occur in the using process, so that insulation breakdown is avoided and the safety performance of the three-position isolation switch is effectively improved.