The present invention provides a signal transmitting method and a base station device. The signal transmitting method is applied to a base station device including a time domain exchanging module and a baseband processing unit, where the time domain exchanging module is connected to the baseband processing unit. The method includes: receiving, by the time domain exchanging module, a first time domain signal transmitted by a user equipment through a radio frequency channel of a serving cell of the user equipment, and receiving a second time domain signal transmitted by the user equipment through a radio frequency channel of a coordinating cell of the user equipment; and transmitting the first time domain signal and the second time domain signal to the baseband processing unit, which is corresponding to the serving cell of the user equipment. Through the present invention, CoMP data exchange can be implemented in an LTE-A system.