Abstract: A novel monocycle pulse generator for road detection ground penetrating radar is designed and demonstrated in this paper. It contains a pulse drive circuit, an step recovery diode(SRD) pulse generating circuit and a pulse forming circuit. The pulse drive circuit can make the TTL signal a sharper and stronger trigger pulse, the SRD pulse generating circuit uses a low transit time diode to produce a negative polarity Gaussian pulse. At last, the pulse forming circuit utilizes micro-strip short circuit line, Schottky diode and capacitor parallel structure to generate monocycle pulse and eliminate the signal ringing. Measurement results show the output of the generator is monocycle pulse with peak values of 23 V at 1 MHz pulse repetition frequency(PRF) and 1.3 ns in full width at half maximum with 1.25% ringing. When the PRF increase to 5 MHz, the amplitude and bandwidth of the pulse generator are almost the same as before. These characteristics show that the pulse generator is pretty stable under high pulse repetition frequency, and will have a very good performance high resolution detection application.