A system information updating method, a user equipment and a base station are provided, the method including: receiving, by the wake-up radio (WUR) interface of the user equipment, a wake-up signal sent by the base station, where the wake-up signal is used to wake up a main radio interface of the user equipment and instruct the main radio interface of the user equipment to receive updated system information, the wake-up signal includes system information (SI) update transmission control information, and the SI update transmission control information includes information required for receiving the updated system information; waking up, by the WUR interface of the user equipment, the main radio interface of the user equipment; and receiving, by the user equipment according to the SI update transmission control information through the woken-up main radio interface, the updated system information sent by the base station.