The invention relates to an isolating switch, a contactor assembly and a contactor thereof. The isolating switch comprises a contactor assembly. The contactor assembly includes a contactor and a contactor seat connected to the contactor. The contactor includes a base having a contact surface for contacting with an adaptive contactor and a connection surface connected with the contact seat. The base is provided with an air guide structure enabling the contact surface to communicate with and the outer space of the base in order to exhaust the air between the contactors to the outer space of the base when the contactor and the adaptive contactors are closed and enable the air of the outer space of the base to enter the contactors when the base and the adaptive contact are closed. Since the contact is provided with the air guide structure, during the opening or closing the isolating switch, the air between the contacts and the air outside the contacts communicate with each other without a sudden pressure change. Thus, the contacts are not influenced by the air between the contacts when operating, the speed of opening and closing the isolating switch is increased, the heat generated by the contact of the contacts is removed, and the heat rate of the contacts is made low.