The present disclosure relates to the field of battery state monitoring technologies, and in particular, to a battery state monitoring method and apparatus. The method is: monitoring a voltage value and a current value of an output end of a battery; determining a battery impedance value based on the voltage value; calculating an impedance voltage-drop value based on the current value and the battery impedance value; calculating an open circuit voltage of the battery based on the voltage value and the impedance voltage-drop value; when a difference of the open circuit voltage between two consecutive calculations is greater than or equal to a threshold, judging that the battery state is abnormal; and when the difference of the open circuit voltage between two consecutive calculations is determined to be lower than the threshold, updating the battery impedance value based on the voltage value and the current value. By using the foregoing method, the battery state is judged by verifying a relationship between a set threshold and a difference of the open circuit voltage between two consecutive calculations, thereby improving the accuracy of battery safety judgment. A possibility of a safety accident occurring in a battery can be predicted, thereby reducing or avoiding a risk of fire outbreak of a device caused due to a battery safety fault of the device.