The invention discloses a transmitter and a user terminal. The transmitter includes a first transformer, a controller and more than two first transmitting branches, wherein the first transformer is suitable for performing impedance conversion on a mixed differential signal and converting the signal subjected to impedance conversion into a single-ended signal under the control of a control signal output by the controller; the controller is coupled with the first transformer and the more than two first transmitting branches, and is suitable for generating and outputting the control signal, wherein the control signal is suitable for controlling the first transformer to convert the mixed differential signal into the single-ended signal and output the signal to an antenna through the corresponding first transmitting branches; and the first transmitting branches are coupled with the controller and the first transformer, and are suitable for outputting the single-ended signal output by the first transformer to the antenna under the control of the control signal output by the controller. By adopting the above scheme, the circuit area occupied by the transmitter and the power consumption can be reduced.