Abstract: Digital transceiver module is an important part of digital array radar (DAR). Through the development of S-band digital T / R module, this paper studies the key technologies such as digital waveform generation and phase shift, digital receiver,highpower amplification and integrated electromagnetic compatibility. In the 300 MHz bandwidth, under the ambient temperature of -40 ℃ ~ + 50 ℃, when the output power is more than 400 W and the noise coefficient is less than 3 dB, the I and Q phase error of the module is 0. 11°, the amplitude error is 0. 1??, and the mirror frequency suppression is more than 58 dB. It lays a technical foundation for the development of advanced digital array radar.