Abstract: The invention discloses a method and system for estimating an SOH of a battery pack, including: measuring an SOH data sequence of each charge and discharge cycle of a battery pack and a terminal voltage and a temperature data sequence of the battery pack of each charging stage; calculating voltage entropy and mean temperature data sequences of the battery pack with the charge and discharge cycle; performing an optimization option on a learning rate of a long short-term memory neural network using a particle swarm algorithm based on the voltage entropy, mean temperature and SOH data sequences of the battery pack with the charge and discharge cycle; establishing an SOH estimation model of the long short-term memory neural network using the learning rate obtained by the particle swarm optimization; and estimating the SOH of the battery pack using the established SOH estimation model of the long short-term memory neural network.