The invention relates to a unipolar millimeter wave cloud measurement radar system and a meteorological measurement method. The cloud measurement radar system comprises a control computer, a signal processing module, a transceiver module, an antenna and a power-on control module. The control computer, the signal processing module, the transceiver module and the antenna are electrically connected in series. The control computer is electrically connected with the power-on control module. The power-on control module is electrically connected with the signal processing module and the transceiver module. According to the invention, a single-transmit and single-receive unipolar system is used; low-power receive and transmit integrated design is used; the system cost is reduced; and large-area networking of the whole system is realized.