Abstract: A ranging measurement based on Linear Frequency Modulated Continuous Laser(LFMCL) heterodynes method was investigated and the system of distance measurement was designed. Mixed the two linear frequency modulated laser beams of the same characteristics which were delayed by delay fiber in different time. Then get the frequency value which contains the ranging information, and simulated by Matlab-Simulink. By the procedure of the linear FM signal and simulation of the linear FM heterodyne ranging, get the the frequency difference of the heterodynes in the distance of 300 meter, 600 meter and 900 meter, the results show that simulation makes a coincidence with the theoretical arithmetic.