An operation mode switching method and user equipment are disclosed, so that an operation mode of the user equipment can be automatically switched. A specific solution is: determining, by user equipment, that a current data transmission rate of the user equipment is less than a first rate threshold, and/or a battery temperature of the user equipment is greater than a first temperature threshold; determining, by the user equipment, that the user equipment is in a CA operation mode; changing, by the user equipment, a transmission mode parameter of the user equipment to a transmission mode parameter corresponding to a non-CA operation mode; and restarting, by the user equipment, a communications module of the user equipment, and sending a first access request to a base station, where the first access request carries the transmission mode parameter corresponding to the non-CA operation mode.