This paper presents an FMCW K-band rain radar with the property of high resolution. The radar system was designed for measurement of localized torrential rain. Using DDS and FPGA control, heterodyne modulation was used to generate the FMCW down-chirp signal with 50 MHz bandwidth, and emitted a K-band signal with nominal power of 125 mW in the vertical direction. To obtain high resolution for the Doppler spectrum, the radar system used a coherent signal processing method. Several experiments were conducted and the results were compared with data from the meteorological administration.