The utility model belongs to the technical field of wireless communication, a prevent under TDD mode that up -downgoing radio frequency link switch is with circuit of opening is disclosed, first, thesecond input pin of first NAND gate are connected with first front end control signal, the second front end control signal who comes from the controller respectively, the output signal of first NAND gate imports respectively to the first input pin of second NAND gate, third NAND gate, the second input pin of second NAND gate is connected with the first front end control signal who comes from the controller, and the second input pin of third NAND gate is connected with the second front end control signal who comes from the controller, the output signal of second NAND gate is as an on -off control signal, is connected to to go upward in the on -off control circuit, the output signal of third NAND gate is connected to in the down on -off control circuit as the 2nd on -off control signal. Theutility model discloses the situation that down link opened simultaneously can be effectively prevented, link circulation self excitation is avoided causing.