Abstract: Chlorine is widely distributed in nature as a major and minor constituent in natural water bodies and salt deposits. The isotopic composition of chlorine serves as a key tracer for understanding the cycling processes of chlorine, and has been extensively applied across various scientific fields including geochemistry, environmental science, and salt deposit analysis. Currently, the mainstream analytical methods for inorganic chlorine isotopes are based on cesium chloride positive thermal ionization mass spectrometry (PTIMS) and chloromethane stable isotope gas ratio mass spectrometry. For organic chlorine isotopes, the primary analytical approaches include multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) and gas chromatography-quadrupole mass spectrometry (GC-qMS) applied to chromatographically separated individual chlorinated organic compounds. This paper systematically reviews the historical development of chlorine isotope measurement techniques, summarizing the background, principles, procedures, current status, advantages, and limitations of each method. Furthermore, it provides an outlook on future directions for the development and application of chlorine isotope analytical techniques, aiming to serve as a reference for the application of chlorine isotope technology in various scientific research fields.