Abstract: After long-term development and improvement, the in-seam seismic(ISS) technology has achieved relatively reliable results in detecting the internal structural development of the coal seam, the thickness variation of the coal seam, and the distribution pattern of the pinch. In order to comprehensively and systematically understand the ISS technology and promote the development of the ISS technology, the status of the ISS technology is reviewed. First, the principle of ISS is briefly described. Then, according to the process of ISS, according to the steps of source excitation, signal acquisition, preprocessing, signal extraction, data processing and analysis, the working principles and methods of related technologies are classified and the excitation modes and signals of different sources are applied. The extraction method and data processing technology were compared and analyzed. Finally, the system summarizes the work and application status of ISS technology in coal thickness analysis, pinch discrimination, structure identification and so on. At present, the coal mine underground ISS technology has certain limitations, and the detection accuracy is difficult to meet the geological exploration requirements. In the future, the development of channel wave radar to improve the accuracy of the ISS is a good development direction.