With the rapid development of microwave and millimeter wave solid-state devices and digital signal processors, Frequency-Modulated Continuous-Wave (FMCW) radar has been widely used in various fields. This paper studies the thickness measurement technology of FMCW, and a FMCW radar front-end working in C-band was designed and implemented. To improve the precision for thickness measurement, a Chirp-Z transform (CZT) algorithm is applied in this paper. Finally, a FMCW radar with a center frequency of 5.8 GHz and a bandwidth of 1 GHz were established, and thickness measurement experiments were carried out. The experimental results demonstrate that the FMCW radar can obtain the sample thickness with low error.