Disclosed herein are a method and device for sensing a surrounding environment based on a frequency modulated continuous wave (FMCW) radar. The method for detecting a target based on an FMCW radar includes the steps of: the FMCW radar transmitting a sensing signal for detection of the target, and receiving a response signal in response to the sensing signal; the FMCW radar performing a signal processing on the response signal, and generating a frequency spectrum of a beat signal; the FMCW radar determining a detection frequency band for detection of the target within a valid frequency band of the frequency spectrum; the FMCW radar determining a threshold value to determine a target detection peak value for detection of the target among peak values of the frequency spectrum; and the FMCW radar detecting the target based on the detection frequency band and the threshold value.