The present disclosure discloses example transmission/reception separation circuits and transceiver. One example transmission/reception separation circuit includes a transmission amplification circuit, an impedance adjustment circuit, and a reception amplification circuit. An output end of the transmission amplification circuit is connected to the impedance adjustment circuit. The impedance adjustment circuit is further connected to an input end of the reception amplification circuit. The second end of the impedance adjustment circuit and the input end of the reception amplification circuit are further configured to be connected to an antenna. The transmission amplification circuit amplifies a first signal to be transmitted. The reception amplification circuit amplifies a second signal received. When the antenna transmits the amplified first signal, a first impedance is in a high impedance state. The impedance adjustment circuit adjusts a second impedance to a high impedance state when the antenna receives the second signal.