The invention relates to a lithium ion battery state of health estimation method. The method includes the following steps that: discharging voltage, discharging current, and discharging time data during the charging and discharging of a lithium ion battery which are performed under a certain working system before and after the aging of the lithium ion battery are obtained; discharging voltage, discharging current, and discharging time data during identical state of charge intervals are intercepted from the data which are obtained in the first step; the state of health indication factor expression of the lithium ion battery is defined; the value of Vlower limit in the third step is obtained; and an HI value in the formula is obtained, and the state of health of the battery is obtained. According to the lithium ion battery state of health estimation method of the invention, the state of health of the lithium ion battery is estimated according to the apparent data (discharging voltage, discharging current, and discharging time data) which can be measured in real time during the work of the battery. The lithium ion battery state of health estimation method of the invention has he advantages of easiness in parameter acquisition, high applicability and real-time application. The lithium ion battery state of health estimation method can be easy to embed a battery management system toestimate the state of health of a battery. The lithium ion battery state of health estimation method can assist in greatly eliminating the defects of existing test systems or test equipment, and is very practical.