Carrier switching method and mobile terminal

The invention provides a carrier switching method and a mobile terminal. The method comprises the following steps: in a downlink carrier aggregation mode, separately obtaining the signal quality of a first component carrier and the signal quality of a second component carrier; if the signal quality of the first component carrier is worse than the signal quality of the second component carrier, separately obtaining a change value of the signal quality of the first component carrier and the change value of the signal quality of the second component carrier; if the change value of the signal quality of the first component carrier is smaller than the change value of the signal quality of the second component carrier, sending a switching request to a base station, so that the base station switches the first component carrier and the second component carrier according to the switching request, so that the second component carrier becomes a main carrier, and the first component carrier becomes an auxiliary carrier.