A scheme of Optical Pulse Compression Reflectometry(OPCR)system based on Nonlinear Frequency Modulation(NLFM)was proposed,which can overcome the shortcoming(high side lobes)of Linear Frequency Modulation(LFM)based OPCR.The optical signal was modulated by NLFM pulse signal in single sideband modulation.Rayleigh scattering and ending reflection signal detected by photodetector was matched filtering by use of the NLFM pulse signal so as to achieve the OPCR reflection trace.Theoretical analysis,numerical simulation and experimental study verify that the NLFM based OPCR system can reduce the magnitude of the side lobes.In the experiment,the measuring range reaches 5.4km although 2km coherence-length laser is used,the spatial resolution is 16.5cm,and the side-lobe suppression rather than LFM is 5.8dB.