A design of L-band stepped frequency ground penetrating radar transceiver system has been proposed. The transmitter generates a continuous wave signal with a frequency band of 1000MHz - 1500MHz and a stepping frequency of 10MHz, and the power flatness is within 3dB through the gain control part. The receiver can self-mix the received signal to generate a beat signal, and convert it into a digital signal through an analog-to-digital converter and send it to the FPGA. After processing the data, the ranging function is complete, achieving an effective 500MHz bandwidth and a 0.1m resolution.