The embodiment of the invention discloses a radio-frequency signal transmitting system, receiving system, transmitting-receiving system and transmitting-receiving method. The transmitting system comprises a center station, wherein the center station comprises a multi-subcarrier modulation module, a radio-frequency modulation module and an optical modulation module; the receiving system comprises a base station; and the base station comprises an optical receiving module, a radio-frequency demodulation module and a multi-subcarrier demodulation module. The transmitting-receiving method comprises the following steps: performing QAM (Quadrature Amplitude Modulation) and multi-subcarrier modulation on data information; performing digital-to-analog conversion and orthogonal modulation; synthesizing N paths of multi-subcarrier analog signals into one path of multi-subcarrier analog signals, and modulating the one path of multi-subcarrier analog signals onto optical carriers; transmitting the one path of multi-subcarrier analog signals to a signal receiving end through an optical fiber after single-sideband modulation; performing power amplification and photoelectric conversion on the signals at the receiving end, distributing the signals to N branches, and demodulating the signals in the branches to obtain baseband electric multi-subcarrier signals; and performing multi-subcarrier demodulation and QAM demodulation to obtain demodulated data, thereby finishing data receiving. Through adoption of the radio-frequency signal transmitting system, receiving system, transmitting-receiving system and transmitting-receiving method in the embodiment of the invention, the bandwidth can be utilized better; the spectrum efficiency is increased; and mutual interference among a plurality of broadband signals is restrained.