Abstract: A battery pack and a state of charge (SOC) estimation method of the battery pack are provided. The method includes estimating an SOC of the battery pack based on a real-time current flowing through the battery pack, where the real-time current is estimated according to real-time parameters of the battery pack, at least part of the real-time parameters of the battery pack are capable of being acquired by querying a battery pack database with at least partially data preset. With the preceding technical solution, a battery pack can be provided which has a low cost and can accurately estimate the SOC of the battery pack without a current detection resistor.