The terahertz radar is getting more and more attention from researchers because of the high resolution it can obtain. The design scheme of a linear frequencymodulated continuouswave terahertz radar operating at 0.22 THz band is proposed in this paper with the experiment results. Lownoise high dynamic range detection comes from the heterodyne RF architecture of the radar. The transmitter of the radar employs direct digital waveform synthesis technology in the baseband to obtain a reliable fast scanning LFMCW source, the scanning speed of which is 40 μs with instantaneous bandwidth of 14.4 GHz. The result of dechirping is coincided with the theoretical value. The fast scanning speed and wide bandwidth characteristics make the radar an ideal candidate for highresolution security inspection and nondestructive detection.