The invention discloses a TR (Transmitter and Receiver) assembly using MC1741 as a power amplifier. The TR assembly comprises a circulator, a switch limiter, an LNA (Low Noise Amplifier), a first filter, a first power amplifier, an attenuator, a TR changeover switch, a third power amplifier, a second filter, a limiter and a second power amplifier. According to the TR assembly disclosed by the invention, by adopting multiple amplification and multiple filter, the gain of signals is ensured while the SNR (Signal Noise Ratio) of the signals is ensured, and certain power is provided for follow-up signal analysis or signal transmitting; meanwhile, the noise coefficient and the gain of each amplifier are limited, and new noise is prevented from being brought in; meanwhile, the original gain which just needs to be subjected to primary amplification is divided into two stages, the noise coefficient is ensured while the amplification gain is amplified, and the purity degree of the signals is ensured.