A new type of broadband microwave sampler is designed in this paper. It can work in 20–50 GHz. The circuit of microwave sampler has the following three parts, including the balun, pulse generator circuit and sampling diode circuit. In the pulse generator circuit, we only use the step recovery diode (SRD) to generate very narrow sampling pulse. Compared with the short circuit microstrip line pulse generator, it can generate higher sampling level. As a result, sampling diodes can be started more easily. This microwave sampler also has good conversion loss and broadband. Return loss of the RF port is better than 10dB. The conversion loss is better than −40 dB, and it is better than −32 dB in 20–40 GHz.