With the advantages of high sensitivity and carrying rich information, laser coherent detection technology has been used widely in military, mapping, communications and other fields. Coherent detection is developing rapidly in laser radar and laser communication applications, but it has not been carried out on a large scale in laser fuze. With coherent detection applied to laser fuze, the speed of targets can be obtained by detecting the laser Doppler signals, and the anti-interference ability of natural environment can be improved greatly by using the velocity difference between the target and the interference. A brief introduction of the principle and the characteristics of coherent detection was given, and then four kinds of coherent laser fuze system, the principle and system composition of a typical linear frequency modulation coherent laser fuze were discussed in detail. At present, coherent laser fuze was still in its infancy, which enhanced the system capabilities obviously and had a broad application prospects, and it deserved further study by relevant research institutes for expediting the engineering application process of coherent laser fuze.