Abstract: Electrochemical Impedance Spectroscopy (EIS) technology has been widely used for online evaluation of the State of Health (SOH) of lithium-ion batteries (LIBs). Currently, significant progress has been made in the research on the SOH evaluation of lithium batteries based on EIS both domestically and internationally. In basic research, the EIS technology is tested based on specific principles, and its parameters are closely related to the battery's health status. The testing process is standardized and orderly, the presentation form of the results is rich and diverse, and it is widely used in various aspects of battery research. In terms of evaluation methods, continuous innovation has been made from analyzing the correlation between parameters to constructing models, but although there have been significant achievements in data processing, it is still plagued by the problems of complex data, model limitations, and real-time issues. This article reviews the research progress of online assessment methods for lithium battery health status based on EIS analysis at home and abroad in recent years, covering the basic principles of EIS technology, common EIS analysis methods, data processing and modeling techniques, as well as its application in battery management systems. The focus was on exploring the challenges and future development directions in current research.