Abstract: Linear frequency modulation continuous wave (LFMCW) radar is an effective sensor for detecting the performance of low-small-slow target (LSS-Target) in the presence of dense architectural clutter, wherein the two-dimensional Fast Fourier transform (2D-FFT) is employed. Firstly, the time and frequency domains of beat frequency signal are analyzed. Secondly, extended to the ground clutter scenario, the influence mechanism of clutter on range and velocity measurements of LSS-Target is analyzed. Finally, by using multiple Monte-Carlo simulations, the comparison of radar parameters (frequency modulation ratio, bandwidth, moving target indication or not etc.), target parameters (RCS, velocity etc.), and clutter parameters (amplitude, spectral width etc.) On detection performance are analyzed. The study shows that the detection in velocity dimension is crucial to discriminate LSS-Target. Meanwhile, it is better to use large bandwidth signal and long-time accumulation technology to improve the target detection performance on strong clutter background.