In order to improve the range resolution of Linear Frequency Modulation Continuous Wave (LFMCW) radar, a cross eight section open loop method is proposed to correct the FM linearity. According to the relationship among LFMCW radar’s actual range resolution, bandwidth and frequency resolution, a 2 GHz large bandwidth and 4096 point FFT operation are selected. The irregular region of beat signal is avoided when computing the frequency and the sampling data is intercepted from the regular region. Simulation and experiments show that the above treatments have brought some improvement to the radar’s range resolution.